Science.gov

Sample records for ocean perch sebastes

  1. An assessment of juvenile Pacific Ocean perch ( Sebastes alutus) habitat use in a deepwater nursery

    NASA Astrophysics Data System (ADS)

    Rooper, Christopher N.; Boldt, Jennifer L.; Zimmermann, Mark

    2007-11-01

    It is believed that juvenile habitats are important to determining recruitment to adult fish populations through density dependence that occurs in nursery areas. For deepwater marine fishes, the characteristics of nursery areas are generally unknown. The objectives of this study were to examine a potential nursery area for juvenile Pacific ocean perch (POP, Sebastes alutus), determine the specific microhabitats used by juvenile POP, and compare the distribution of juvenile POP to adults. Juvenile POP habitat use was examined at three sites near Samalga Pass in the Aleutian Islands. Presence or absence and density estimates of juvenile POP were made from underwater video collected at 11 transects and from 6 bottom tows at the study sites. Juvenile POP were found predominantly in mixed sand and boulder substrata to the exclusion of most other habitat types. Juvenile POP were found within one body length of complex structure such as boulders, upright coral or sponges. There were higher densities of juvenile POP at the site south of Samalga Pass than at the other sites, while adult POP were found in highest abundance at the site north of Samalga Pass. An examination of large-scale patterns of juvenile and adult POP distribution indicates that juveniles use shallower depth zones on the continental shelf. Combined with the geographic separation we observed in this study, this suggests juvenile POP use nursery habitats that are different from adult POP. Conservation and management of this species should address the habitat requirements of juveniles to maintain the goal of healthy adult populations.

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

    NASA Astrophysics Data System (ADS)

    Coffin, Brendan; Mueter, Franz

    2016-10-01

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

  3. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... 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... ocean perch total allowable catch specified for vessels participating in the Amendment 80 limited...

  5. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... 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...

  7. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-21

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

  9. 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...

  10. 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...

  11. 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...

  12. 78 FR 44465 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... 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 2013 total allowable catch (TAC) of Pacific ocean perch in the West Yakutat District of the...

  13. 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...

  14. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-01

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

  16. 76 FR 46207 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-02

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level...; 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...

  17. 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...

  18. 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...

  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. 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...

  2. 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...

  3. 77 FR 42439 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Ocean Perch in the West Yakutat...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-19

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

  4. 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...

  5. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

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

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ... 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 2010 total allowable catch of Pacific ocean...

  8. 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... available data and finds that the ITAC for Pacific ocean perch in the Bering Sea subarea needs to...

  9. Identification of Pacific rockfish (Sebastes) species by isoelectric focusing.

    PubMed

    Lundstrom, R C

    1983-07-01

    Isoelectric focusing (IEF) is currently the most reliable method available for the identification of fish species. The high resolution of this method usually allows discrimination between even closely related species. One genus, the Sebastes, does present a problem however. Using both low and high resolution, IEF is unable to differentiate several species. Disc electrophoresis, used in an AOAC official final action method, does not differentiate the rockfish reliably. Using IEF, identical protein patterns were obtained for Pacific Ocean perch (Sebastes alutus), Bocaccio rockfish (S. paucispinis), and yelloweye rockfish (S. ruberrimus). A second group, comprised of silvergray rockfish (S. brevispinis), yellowtail rockfish (S. flavidus), black rockfish (S. melanops), and canary rockfish (S. pinniger), also has identical protein patterns. Widow rockfish (S. entomelas) and chilipepper rockfish (S. goodei) each had a unique pattern, different from the above 2 groups and from each other. The actual taxonomic relationships of these rockfish species are not clear and further work with IEF may help in this regard. Users of IEF and disc electrophoresis for identification purposes should be aware of this problem when working with the Sebastes.

  10. 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...

  11. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-07

    ... Economic Zone Off Alaska; Pacific Ocean Perch for Catcher Vessels Participating in the Rockfish Entry Level...; 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. 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

    ... National Oceanic and Atmospheric Administration 50 CFR Part 679 RIN 0648-XC757 Fisheries of the Exclusive...: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce... 2013 and 2014 harvest specifications for groundfish in the BSAI (78 FR 13813, March 1, 2013)....

  19. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE...: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce... 2013 and 2014 harvest specifications for groundfish in the BSAI (78 FR 13813, March 1, 2013)....

  20. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE...: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce... 2013 and 2014 harvest specifications for groundfish in the BSAI (78 FR 13813, March 1, 2013)....

  1. Genetic evidence of postglacial population expansion in Puget Sound rockfish (Sebastes emphaeus).

    PubMed

    Sotka, Erik E; Hempelmann, Jennifer A; Biermann, Christiane H

    2005-01-01

    Several rockfish species (genus Sebastes) along the northeastern Pacific Ocean have rapidly declined in abundance owing in part to overfishing. A striking exception is the dwarf-like Puget Sound rockfish Sebastes emphaeus, whose densities have increased by several orders of magnitude over the last several decades. To describe their genetic structure, we sequenced 395 bp from the mitochondrial control region of 128 S. emphaeus adults from 5 locations spanning approximately 120 km of the Northwest Straits of Washington state. We detected no significant genetic differentiation among these populations and substantial genetic variation within populations, a pattern that may indicate high levels of ongoing gene flow. Preliminary data from 2 microsatellite loci are also consistent with panmixia. The mtDNA sequences also suggest that Puget Sound rockfish populations have expanded substantially since the retreat of Pleistocene glaciers made habitat in Puget Sound region available approximately 12,000 years ago.

  2. 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

  3. Kudoa miniauriculata n. sp. (Myxozoa, Myxosporea) from the musculature of bocaccio (Sebastes paucispinis) from California.

    PubMed

    Whitaker, D J; Kent, M L; Sakanari, J A

    1996-04-01

    A new species of Myxosporea Kudoa miniauriculata is described from the somatic muscle of bocaccio (Sebastes paucispinis), an eastern Pacific Ocean rockfish species caught off the coast of California. Spores are stellate in apical view and suboval in side view. The tip of each valve is uplifted. Each valve has a small (0.25-0.41 micron) projection at its apical end. Mean spore dimensions were width 7.94 microns, length 5.41 microns, and polar capsule length 2.15 microns. A previous identification of K. clupeidae in bocaccio and the presence of this species on the west coast of North America is discounted.

  4. 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.

  5. 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.

  6. Isolation and Characterization of Twelve Microsatellite Loci for Rockfish (Sebastes).

    PubMed

    Wimberger; Burr; Gray; Lopez; Bentzen

    1999-05-01

    : We describe the first microsatellites for rockfishes in the diverse genus Sebastes. Clones containing microsatellites were isolated from the genomic library of a quillback rockfish, Sebastes maliger. Twelve microsatellites are characterized; six of these are polymorphic in quillback rockfish, and eight are polymorphic in at least one rockfish species on which they were tested. The number of alleles per variable locus ranged from 4 to 15 and averaged 6.8. The expected heterozygosities ranged from 0.38 to 0.79 and averaged 0.60 in these loci. These loci should prove valuable in studies examining species identification, population genetics, hybridization, paternity, kinship, and microsatellite evolution. PMID:10384005

  7. Perch width preferences of laying hens.

    PubMed

    Struelens, E; Tuyttens, F A M; Ampe, B; Odberg, F; Sonck, B; Duchateau, L

    2009-07-01

    1. In order to investigate the effect of perch width on perching behaviour of laying hens, two experiments in which hens could choose between 7 different perch widths (1.5, 3.0, 4.5, 6.0, 7.5, 9.0 and 10.5 cm) were conducted. In one experiment (EXP-2P) test cages contained two long perches gradually broadening and narrowing stepwise, in the other experiment (EXP-7P) 7 separate short perches differing in width were placed in the test cages. In each experiment 12 groups of 4 hens were filmed during day and night. The behaviour and location of the hens were recorded and whether the nest box affected hen distribution over the perches was investigated. 2. During daytime, in EXP-2P, there was an increase in perch use with increasing perch width. Hens spent less time on perches of 1.5 cm wide compared to perches of 9.0 and 10.5 cm wide. In EXP-7P, the 1.5-cm wide perch was also used the least (but only the difference with 4.5-cm wide perches was statistically significant) but perch use did not increase linearly with perch width. During the night, there were no significant perch width preferences in either experiment. 3. The percentage of active behaviours (preening, walking, drinking, pecking at hen) versus passive behaviours (standing, sitting, sleeping) did not differ significantly according to perch width. 4. In EXP-7P, there was a trend for perch use to decrease with greater distances to the nest box in the morning. 5. A perch width of 1.5 cm is not recommended for laying hens. For wider perch widths, results were equivocal: they tend to support rather than challenge the widespread use of 4.5-cm wide perches in commercial units.

  8. 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.

  9. 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'.

  10. 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.

  11. General behaviors and perching behaviors of laying hens in cages with different colored perches.

    PubMed

    Chen, D H; Bao, J

    2012-05-01

    Color is one of the perch properties. This study was conducted to investigate the general behaviors and perching behaviors in laying hens under different group size (stocking density), and to understand the perch color (black, white or brown) preference of hens during the night. A total of 390 Hyline Brown laying hens was used, and randomly allocated to three treatments: individual group (G1), group of four hens (G4), and group of eight hens (G8), respectively. There were 30 replicates in each group. The hens in G1, G4 and G8 groups were put into the test cages in which three colored perches were simultaneously provided and allowed for four days of habituation in the new cages. Hens behaviors were recorded using cameras with infrared light sources for the following periods: 8:00 to 10:00; 14:00 to 16:00; 19:00 to 21:00; 23:30 to 0:30 on the fifth day after transferring the birds into the test cages. The behaviors of hens in every time period were collected and analyzed, and hens positions on the test perches during mid-night were recorded. The results showed that, group size (stocking density) had significant effect on most of the general behaviors of laying hens except exploring behavior. There were great differences in most of the general behaviors during different time periods. In the preference test of perch color during night, the hens showed no clear preference for white, black or brown perches. For perching behaviors, perching time and frequency of transferring from one perch to another was higher on black perches than on white or brown perches in individual groups. In G4 groups, the hens spent more time on white perches during daytime and more frequent transferring during night compared with black or brown perches. The frequency of jumping upon and down from white perches was higher in G8 groups. It can be concluded that although the group sizes in the cage significantly affected most of the general behaviors, we found that no preference of perch color was

  12. Chromatophoromas and chromatophore hyperplasia in Pacific rockfish (Sebastes spp.).

    PubMed

    Okihiro, M S; Whipple, J A; Groff, J M; Hinton, D E

    1993-04-15

    Pacific rockfish from Cordell Bank, off central California (United States), were collected and histologically examined from 1985 to 1990. Hyperplastic and neoplastic cutaneous lesions, involving dermal chromatophores, were observed in five species; yellowtail rockfish (Sebastes flavidus), bocaccio (S. paucispinis), olive rockfish (S. serranoides), widow rockfish (S. entomelas), and chilipepper rockfish (S. goodei). Yearly prevalences were highest in S. paucispinis (29-38%). Prevalence was initially low in S. flavidus, but increased more than 3-fold from 1985 (7.5%) to 1990 (25%). The majority of lesions were black, but white, yellow, orange, red, and mixed-color variants were also seen. Lesions were found in skin, fins, lips, gingiva, tongue, urogenital papilla, conjunctiva, and cornea of the eye. Flat lesions were consistent with melanophore (black), xanthophore (yellow or orange), and erythrophore (red) hyperplasia. Neoplastic lesions included melanophoromas, amelanotic melanophoromas, xanthophoromas, erythrophoromas, and mixed chromatophoromas. Although etiology has not been determined, interest is currently focused on potential exposure to chemical and radioactive carcinogens from the Farallon Island Radioactive Waste Dump, 30 km to the south.

  13. 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.

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

    USGS Publications Warehouse

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

    2010-01-01

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

  15. 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.

  16. 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.

  17. Subtle population genetic structure in yelloweye rockfish (Sebastes ruberrimus) is consistent with a major oceanographic division in British Columbia, Canada.

    PubMed

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

    2013-01-01

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

  18. Subtle population genetic structure in yelloweye rockfish (Sebastes ruberrimus) is consistent with a major oceanographic division in British Columbia, Canada.

    PubMed

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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  20. Effect of perches on liver health of hens.

    PubMed

    Jiang, S; Hester, P Y; Hu, J Y; Yan, F F; Dennis, R L; Cheng, H W

    2014-07-01

    Fatty liver is a common energy metabolic disorder in caged laying hens. Considering that the egg industry is shifting from conventional cages to alternative housing systems such as enriched cages, the objective of this study was to determine the effects of perches on fat deposition and liver health in laying hens. Three hundred twenty-four 17-wk-old White Leghorn hens were housed in 1 of 4 treatments with 9 hens per cage. Treatment 1 hens never had access to perches during their life cycle. Treatment 2 hens had access to perches during the pullet phase only. Treatment 3 hens had access to perches during the laying phase only. Treatment 4 hens always had access to perches. Liver weight, abdominal fat pad weight, BW, liver fat, and circulating alanine transaminase, aspartate transaminase, and adiponectin were determined. Provision of perches during either the rearing or laying phase did not affect liver health in 71-wk-old hens. However, perch access compared with no perch access during the egg laying phase reduced relative fat pad weight. These results suggest that providing perches as a means of stimulating activity reduced abdominal fat deposition in caged hens during the laying period. However, perch access in caged hens was ineffective in reducing fat deposition in the liver and altering enzyme activities related to improved liver function. PMID:24812236

  1. Effect of perches on liver health of hens.

    PubMed

    Jiang, S; Hester, P Y; Hu, J Y; Yan, F F; Dennis, R L; Cheng, H W

    2014-07-01

    Fatty liver is a common energy metabolic disorder in caged laying hens. Considering that the egg industry is shifting from conventional cages to alternative housing systems such as enriched cages, the objective of this study was to determine the effects of perches on fat deposition and liver health in laying hens. Three hundred twenty-four 17-wk-old White Leghorn hens were housed in 1 of 4 treatments with 9 hens per cage. Treatment 1 hens never had access to perches during their life cycle. Treatment 2 hens had access to perches during the pullet phase only. Treatment 3 hens had access to perches during the laying phase only. Treatment 4 hens always had access to perches. Liver weight, abdominal fat pad weight, BW, liver fat, and circulating alanine transaminase, aspartate transaminase, and adiponectin were determined. Provision of perches during either the rearing or laying phase did not affect liver health in 71-wk-old hens. However, perch access compared with no perch access during the egg laying phase reduced relative fat pad weight. These results suggest that providing perches as a means of stimulating activity reduced abdominal fat deposition in caged hens during the laying period. However, perch access in caged hens was ineffective in reducing fat deposition in the liver and altering enzyme activities related to improved liver function.

  2. 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

  3. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  5. 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.

  6. 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.

  7. 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

  8. 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...

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

    PubMed

    Ingram, Travis; Kai, Yoshiaki

    2014-11-01

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

  10. 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.

  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. 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

  13. Development and evaluation of a SUAS perching system

    NASA Astrophysics Data System (ADS)

    Reynolds, Ryan

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

  14. 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.

  15. Influence of Dietary Ascorbic Acid on the Immune Responses of Juvenile Korean Rockfish Sebastes schlegelii.

    PubMed

    Kim, Jun-Hwan; Kang, Ju-Chan

    2015-09-01

    Juvenile Korean Rockfish Sebastes schlegelii (length, 13.6 ± 1.4 cm [mean ± SD]; weight, 53.6 ± 4.2 g) were fed twice daily with diets containing varying levels of ascorbic acid (0, 50, 100, 200, and 400 mg/kg) for 4 weeks. Significant increases in daily weight and length occurred in fish fed more than 50 mg/kg ascorbic acid. The lysozyme activity of fish fed diets containing ascorbic acid was considerably increased in rockfish plasma at 400 mg/kg ascorbic acid and in kidney at over 50 mg/kg ascorbic acid. Total plasma immunoglobulin M (IgM) levels were markedly elevated in fish fed 400 mg/kg ascorbic acid. The results suggest that dietary ascorbic acid supplementation in juvenile rockfish can induce a significant increase in growth and in immunological features such as lysozyme activity and plasma IgM levels.

  16. 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.

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

    USGS Publications Warehouse

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

    1999-01-01

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

  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; 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.

  19. 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.

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

    EPA Science Inventory

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

  2. Thermal acclimation in the perch (Perca fluviatilis L.) immunity.

    PubMed

    Marnila, Pertti; Lilius, Esa-Matti

    2015-12-01

    Fish immune systems must be able to cope with pathogens over a wide temperature range. Earlier research suggest that fish are more dependent on innate immune responses based on pattern recognition than acquired functions with specific recognition. If this applies to phagocytes, then opsonins (serum factors that augment phagocytosis e.g. immunoglobulins and complement proteins) attached on zymosan (Z) particles should be recognized better at higher temperatures than Z only. Z is recognized by glucan receptor representing pattern recognition. In this study perch were acclimated to 5 °C or 16 °C for 3-5 weeks. The recognition and activation of respiratory burst reaction of peripheral blood phagocytes was examined at seven different measurement temperatures (5, 10, 16, 20, 24 27, and 30 °C) when the cells were stimulated with Z and serum opsonized zymosan (OZ). Respiratory burst was measured as luminol chemiluminescence (CL) from diluted whole blood. OZ-induced CL per volume of blood was on average approximately 4.6 times higher in 16 °C acclimated fish than 5 °C acclimated perch (P<0.0001). Z-induced CL was approximately 3 times higher at lower temperatures in 16 °C acclimated perch than 5 °C acclimated fish and 6-9 times higher at 27 °C and 30 °C (P<0.001), respectively. CL reaction kinetics were faster in perch acclimated to 5 °C than 16 °C -acclimated fish, especially at low temperatures (P<0.001). Thermal acclimation caused a 3-4 °C shift in temperature response curves of CL towards the acclimation temperature (P<0.0001 and P<0.053 in Z and OZ-induced CL, respectively). Serum opsonins activated perch phagocytes substantially better at higher temperatures in both acclimation groups, which is consistent with an earlier study in rainbow trout (O. mykiss). However, opsonin recognition was significantly better in 16 °C acclimated perch than 5 °C acclimated fish, which was seen as higher CLs for OZ compared to Z, especially at higher temperatures. This is

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

    PubMed

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

    2005-05-01

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

  4. 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.

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

    PubMed

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

    2015-04-01

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

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  9. 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...

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. Replicate divergence between and within sounds in a marine fish: the copper rockfish (Sebastes caurinus).

    PubMed

    Dick, S; Shurin, J B; Taylor, E B

    2014-02-01

    Understanding the factors that influence larval dispersal and connectivity among marine populations is critical to the conservation and sustainable management of marine resources. We assessed genetic subdivision among ten populations of copper rockfish (Sebastes caurinus) representing paired samples of outer coast and the heads of inlets in five replicate sounds on the west coast of Vancouver Island, British Columbia, using 17 microsatellite DNA loci. Overall, subdivision (F(ST)) was low (F(ST) = 0.031, P < 0.001), but consistently higher between paired coast and head of inlet sites (mean FST = 0.047, P < 0.001) compared to among the five coast sites (mean F(ST) = -0.001, P > 0.5) or among the five head of inlet sites (mean F(ST) = 0.026, P < 0.001). Heterozygosity, allelic richness and estimates of effective population size were also lower in head of inlet sites than in coast sites. Bayesian analysis identified two genetic groups across all samples, a single genetic group among only coast samples, two genetic groups among head of inlet samples and two genetic groups within each sound analysed separately. Head of inlet copper rockfish tended to be shorter with lower condition factors and grew more slowly than coast sites fish. Reduced physical connectivity and selection against immigrants in contrasting outer coast-head of inlet environments likely contribute to the evolution of population structure of copper rockfish. Based on genetic connectivity, coast sites appear to be better served by existing marine protected areas than are head of inlet sites.

  16. Characterization of a genomic divergence island between black-and-yellow and gopher Sebastes rockfishes.

    PubMed

    Buonaccorsi, Vincent P; Narum, Shawn R; Karkoska, Kristine A; Gregory, Steven; Deptola, Travis; Weimer, Alexander B

    2011-06-01

    Islands of high genomic divergence that contain genes of evolutionary significance may form between diverging species. The gopher rockfish, Sebastes carnatus, and black-and-yellow rockfish, S. chrysomelas, are sympatrically distributed temperate marine species inhabiting rocky reefs and kelp forests on the west coast of the United States. Prior studies documented low levels of genetic divergence between the two species, except at a single microsatellite locus that displayed high divergence, Sra.7-2. To better characterize genome wide divergence, we scored 25 additional microsatellite loci. Mean neutral divergence between species (F(ST) = 0.01) changed little from prior estimates. Sra.7-2 continued to be an extreme divergence outlier. Five novel microsatellites within ± 15 kb of Sra.7-2 were characterized. High divergence, consistently low diversity in S. chrysomelas, and linkage disequilibrium were detected at these loci, suggesting the influence of recent selection. However, coalescent modelling of divergence at neutral and Sra.7-2 regions showed that initial divergence at Sra.7-2 was ancient, likely predating divergence at neutral regions. It is therefore unlikely that Sra.7-2 divergence represents solely recent ecological divergence within one species and may represent the action of recurrent selection. Introgressive gene flow (2N(E) m) was much higher (>1) at neutral than Sra.7-2 regions (<1) despite evidence that two S. carnatus individuals have recently mixed ancestry at the Sra.7-2 region. The Sra.7-2 genomic region is likely one of several regions containing genes involved in initiating and maintaining species integrity. Completion of the final stages of speciation appears to be a slow and ongoing process for these species. PMID:21557784

  17. 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

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

    PubMed

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

    2012-08-01

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

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

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

    USGS Publications Warehouse

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

    1998-01-01

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

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

    PubMed

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

    2013-10-11

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

  6. Field test of two energetic models for yellow perch

    USGS Publications Warehouse

    Schaeffer, J.S.; Haas, R.C.; Diana, J.S.; Breck, J.E.

    1999-01-01

    Field data from a population of yellow perch Perca flavescens in Saginaw Bay, Lake Huron, were used to evaluate the ability of two energetic models to predict consumption by yellow perch. Field estimates of daily ration for age-l-4 fish during May through October 1987 and 1988 were compared with independent predictions made by the Wisconsin energetic model and an energetic model developed by Karas and Thoresson. Predictions of daily ration using the Wisconsin model were lower than daily rations estimated from field data for all ages, primarily due to poor model-field agreement at temperatures above 22??C. This caused estimates of cumulative consumption from the Wisconsin model to be 25-50% lower than field estimates. Predictions of daily ration by the Karas-Thoresson model agreed with field estimates over a temperature range of 1026??C for age-1-3 yellow perch but not for older fish. Despite improvement, model predictions of cumulative consumption were 2-35% lower than field estimates. Although these tests of predicted and estimated rations may provide insight into which model produced more accurate results, it must be emphasized that field measures of daily ration are also estimates and may be in error, particularly at temperatures above 22??C where gastric evacuation rates were estimated. The Karas-Thoresson modification of the Wisconsin energetic model produced better fits to field ration data and is recommended for model applications.

  7. 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.

  8. 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.

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

    PubMed

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

    2013-03-01

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

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

    USGS Publications Warehouse

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

    2014-01-01

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

  11. 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

  12. 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.

  13. 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

  14. Effects of sodium cyanide (nacn) on the endogenous rhythm of the oxygen consumption rate in the black rockfish sebastes schlegeli

    NASA Astrophysics Data System (ADS)

    Kim, Wan Soo; Kim, Jong Wook; Lee, Jae Hak; Huh, Sung Hoe

    2008-06-01

    Laboratory bioassays were conducted to test the acute toxicity effects of sudden exposure to sodium cyanide (NaCN) on the endogenous rhythm of the oxygen consumption rate (OCR) in the black rockfish Sebastes schlegeli. The OCR of the black rockfish (n = 14, total length = 20.4 ± 1.16 cm, wet weight = 158 ± 25 g) was measured with an automatic intermittentflow-respirometer. OCR decreased significantly when experimental fish were exposed to NaCN. When exposed to 10 ppb NaCN, fish were able to recover their OCR rhythmic activities. When fish were exposed to 20 ppb, however, the metabolic activity rhythms were not recovered. These results suggest that exposure to NaCN concentrations over 20 ppb cause severe physiological damage to the endogenous rhythms of black rockfish.

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

    USGS Publications Warehouse

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

    2002-01-01

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

  16. 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

  17. 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

  18. 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...

  19. 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...

  20. 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...

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

    PubMed

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

    2014-10-01

    Enriched cages, compared with conventional cages, allow egg laying strains of chickens to meet some behavioral needs, including a high motivation to perch. The objective of this study was to determine if perch availability during rearing affected perch use as adults and if perch presence affected eating and drinking in caged White Leghorn hens. Chickens were assigned to 14 cages each with and without 2 round metal perches from hatch to 16.9 wk of age. At 17 wk of age, pullets were assigned to laying cages consisting of 1 of 4 treatments. Treatment 1 chickens never had access to perches (controls). Treatment 2 chickens only had access to 2 round metal perches during the laying phase (17 to 71 wk of age). Treatment 3 chickens only had access to 2 round perches during the pullet phase (0 to 16.9 wk of age). Treatment 4 chickens had access to the perches during both the pullet and laying phase. Each treatment during the adult phase consisted of 9 cages with 9 birds/cage for a total of 36 cages. Automatic infrared cameras were used to monitor behavior of hens in each cage for a 24-h period at 19, 24, 29, 34, 39, 44, 49, 54, 59, 64, and 69 wk of age. Behavior was also recorded twice weekly by an observer in the room where the hens were housed during photophase from 25 to 68 wk of age. Behavioral data were analyzed using ANOVA with repeated measures and the MIXED model procedure. A greater proportion of hens without perches as pullets used the rear perch more during both photophase and scotophase than hens with prior pullet perching experience. Eating and drinking activities of caged adult Leghorns were not impaired by their prior experience to perches as pullets or by the presence of perches in laying cages. It is concluded that providing perches in cages to White Leghorns during pullet rearing did not facilitate use of perches as adults. PMID:25125558

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

    PubMed

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

    2014-10-01

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

  3. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

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

    PubMed

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

    2011-12-01

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

  11. 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.

  12. 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.

  13. A mockingbird perches on a limb at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

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

  14. 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.

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

    USGS Publications Warehouse

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

    1990-01-01

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

  16. 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

  17. 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

  18. Comparative population genetic analysis of bocaccio rockfish Sebastes paucispinis using anonymous and gene-associated simple sequence repeat loci.

    PubMed

    Buonaccorsi, Vincent P; Kimbrell, Carol A; Lynn, Eric A; Hyde, John R

    2012-01-01

    Comparative population genetic analyses of traditional and emergent molecular markers aid in determining appropriate use of new technologies. The bocaccio rockfish Sebastes paucispinis is a high gene-flow marine species off the west coast of North America that experienced strong population decline over the past 3 decades. We used 18 anonymous and 13 gene-associated simple sequence repeat (SSR) loci (expressed sequence tag [EST]-SSRs) to characterize range-wide population structure with temporal replicates. No F(ST)-outliers were detected using the LOSITAN program, suggesting that neither balancing nor divergent selection affected the loci surveyed. Consistent hierarchical structuring of populations by geography or year class was not detected regardless of marker class. The EST-SSRs were less variable than the anonymous SSRs, but no correlation between F(ST) and variation or marker class was observed. General linear model analysis showed that low EST-SSR variation was attributable to low mean repeat number. Comparative genomic analysis with Gasterosteus aculeatus, Takifugu rubripes, and Oryzias latipes showed consistently lower repeat number in EST-SSRs than SSR loci that were not in ESTs. Purifying selection likely imposed functional constraints on EST-SSRs resulting in low repeat numbers that affected diversity estimates but did not affect the observed pattern of population structure.

  19. 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.

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

    PubMed

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

    2015-11-01

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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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

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

    PubMed

    Palmer, Alexander D; Emmenegger, Eveline J

    2014-06-01

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

  9. 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

  10. The effect of perch availability during pullet rearing and egg laying on musculoskeletal health of caged White Leghorn hens.

    PubMed

    Hester, P Y; Enneking, S A; Haley, B K; Cheng, H W; Einstein, M E; Rubin, D A

    2013-08-01

    A major skeletal problem of conventionally caged hens is increased susceptibility to osteoporosis mainly due to lack of exercise. Osteoporosis is characterized by a progressive decrease in mineralized structural bone. Whereas considerable attention has been given to enriching laying cages, little research has been conducted on providing caged pullets with furnishments, in particular perches. The objective of the current study was to determine if metal perches during all or part of the life cycle of White Leghorns affected hen musculoskeletal health, especially at end of lay. Treatments during the pullet phase (hatch to 16.9 wk) entailed cages with and without perches. Four treatments were used during the laying phase (17 to 71 wk of age). Treatment 1 chickens never had access to perches at any point during their life cycle, typical of egg industry practices in the United States for conventional cages. Treatment 2 chickens had access to perches only during the egg-laying phase, which was from 17 to 71 wk of age. Treatment 3 chickens had access to perches only during the pullet phase (0 to 16.9 wk of age). Treatment 4 chickens had perch access throughout their entire life cycle (0 to 71 wk of age). Musculoskeletal health was assessed by measuring muscle weights, bone mineralization, bone fracture incidence, and keel bone deviations. Muscle deposition of 71-wk-old hens increased when given access to perches as pullets. Bone mineralization of 71-wk-old hens also increased if given perch access as adults. However, the disadvantage of the adult perch was the higher incidence of keel deviations and keel fractures at end of lay. The increase in bone mineralization of the keel bone as a result of perch access during the pullet and laying phases was not great enough to prevent a higher incidence of keel bone fractures at end of lay. Perch redesign and placement of perches within the cage to minimize keel fractures and deviations are possible solutions. PMID:23873543

  11. 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.

  12. 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).

  13. 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.

  14. 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

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

    USGS Publications Warehouse

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

    1993-01-01

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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Molecular and pharmacological properties of GABA-rho subunits from white perch retina.

    PubMed

    Qian, H; Dowling, J E; Ripps, H

    1998-11-01

    Five gamma-aminobutyric acid (GABA)-rho subunits were cloned from a white perch retinal cDNA library and expressed in Xenopus oocytes. The deduced amino acid sequences indicated that all are highly homologous to the GABA-rho subunits cloned from mammalian retinas; two clones (perch-rho 1A and perch-rho 1B) were in the rho 1 family, two (perch-rho 2A and perch-rho 2B) were in the rho 2 family, and one clone has been tentatively identified as a perch-rho 3 subunit. When expressed in Xenopus oocytes, all but one of the subunits (rho 3) formed functional homooligomeric receptors. However, the receptors expressed by each of the GABA-rho subunits displayed unique response properties that distinguished one from the other. For example, receptors formed by perch-rho 1B subunits were more sensitive to GABA than the receptors formed by other GABA-rho subunits, the dose-response curves for the various receptors revealed different Hill coefficients, and there were differences in the kinetics of the GABA-induced currents. In addition, the GABA-mediated current-voltage curve for rho 2 receptors was approximately linear, whereas the responses from rho 1 receptors showed outward rectification. A further division in the properties of the GABA-rho subunits was revealed in their responses to imidazole-4-acetic acid (I4AA); the drug behaved as an antagonist on A-type rho receptors and a partial agonist on the B-type rho receptors. These results suggest that there is a large diversity of GABAC receptors in the vertebrate retina, probably formed by homooligomeric and heterooligomeric combinations of GABA rho subunits, that exhibit different functional properties. PMID:9805275

  1. 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).

  2. Selection of reference genes for reverse transcription quantitative real-time PCR normalization in black rockfish (Sebastes schlegeli).

    PubMed

    Liman, Ma; Wenji, Wang; Conghui, Liu; Haiyang, Yu; Zhigang, Wang; Xubo, Wang; Jie, Qi; Quanqi, Zhang

    2013-09-01

    Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is a technique widely used for quantification of mRNA transcription. Data normalization is an indispensable process for RT-qPCR and reference genes are most commonly used to normalize RT-qPCR and to reduce possible errors generated in the quantification of genes among several proposed methods. To date, RT-qPCR has been used in terms of gene expression studies in black rockfish (Sebastes schlegeli) but the majority of published RT-qPCR studies still lack proper validation of the reference genes. In the present study, mRNA transcription profiles of eight putative reference genes (18S rRNA, ACTB, GAPDH, TUBA, RPL17, EF1A, HPRT, and B2M) were examined using RT-qPCR in different tissues and larvae developmental stages of black rockfish. Three common statistical algorithms (geNorm, NormFinder, and BestKeeper) were used to assess expression stability and select the most stable genes for gene normalization. Two reference genes, RPL17 and EF1A showed high stability in black rockfish tissue analysis, while GAPDH was the least stable gene. During larvae developmental stages, EF1A, RPL17 and ACTB were identified as the optimal reference genes for data normalization, whereas B2M appeared unsuitable as the reference gene. In summary, our results could provide a useful guideline for reference gene selection and enable more accurate normalization of gene expression data in gene expression studies of black rockfish.

  3. The physiology functions of estrogen receptor α (ERα) in reproduction cycle of ovoviviparous black rockfish, Sebastes schlegeli Hilgendorf.

    PubMed

    Shi, Dan; Wen, Hai S; He, Feng; Li, Ji F; Yang, Yan P; Chen, Cai F; Zhang, Jia R; Chen, Xiao Y; Jin, Guo X; Shi, Bao; Qi, Bao X; Li, Na

    2011-12-20

    This paper revealed the expression pattern of ERα in the ovoviviparous teleost, Sebastes schlegeli. In this paper, we isolated the cDNA encoding for estrogen receptor alpha of black rockfish (S. schlegeli) from its ovary, named as black rockfish ERα (brfERα). The cDNA sequence of brfERα consists of 2972bp with an open reading frame encoding a 624 amino acid putative protein which exhibits high identities with other teleosts'. The tissue distribution of brfERα mRNA was examined using RT-PCR. BrfERα showed generally expressions in most tissues of female black rockfish, besides, the higher degree of expressions were seen in ovary, liver, duodenum and fat, whereas it had a more restricted distribution in male fish. In ovary, the expression level of brfERα was as similar as the serum levels of E2 and P in female. However, it was a different situation in male, where the serum concentration of E2 showed higher levels after spermiation and Serum concentration of P did not show any significant changes during a year. Based on the present study, it is supposed that brfERα plays an important role in ovary and other target organs during the reproductive cycle, Further studies will focus on the transcriptional regulation and localization of brfERα in gonad in order to get a better understand of the physiological function of brfERα in ovoviviparous teleost. This study indicates that the black rockfish may be a good candidate for understanding the mechanism of estrogen in ovoviviparous fish.

  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. Influence of environmental enrichment on injurious pecking and perching behaviour in young turkeys.

    PubMed

    Martrenchar, A; Huonnig, D; Cotte, J P

    2001-05-01

    1. In order to reduce injurious pecking, the influence of environmental enrichment on pecking and perching behaviour was studied in young male and female turkeys. 2. Two different types of enrichment and a control treatment (TO) were tested: T1, metal objects and straw; T2, similar to T1 + wood perches. Birds were housed in 36 m2 pens at a light intensity of 5 lux with 4 replicates per treatment in a 2x3 factorial design. 3. Pecking at objects and perching behaviour were observed weekly. Behaviour was video recorded at weeks 5 and 10. Birds were examined daily for the occurrence of injuries. At the end of the rearing period, an ACTH challenge was performed and H/L ratio was measured. 4. Objects were regularly pecked at. Perching was more common in females, peaked at week 5 (10% to 13% of birds perched) and declined to 0% by week 10. Aggressive pecking was more frequently observed in males in T0 than in T1 or T2 at week 10. Wing (in males and females), tail and head (in males) injuries were more common in T0 than in T1 or T2. T1 and T2 were similar Response to ACTH challenge and H/L ratio were not consistently influenced by treatments. 5. It is concluded that metal objects and straw reduced injurious pecking in young female and male turkeys by redirecting, pecking activity.

  6. 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.

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

    PubMed

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

    2011-09-01

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

  8. 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

  9. 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

  10. 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

  11. 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

  12. Use of perches and seed dispersal by birds in an abandoned pasture in the Porto Ferreira state park, southeastern Brazil.

    PubMed

    Athiê, S; Dias, M M

    2016-02-01

    We investigated the efficiency of different kinds of perches in attracting seed disperser-birds and increasing the seed rain in a degraded area located in the northeast region of São Paulo State. We installed seed traps under natural perches (NPs, living trees); simple artificial perches (SAPs) of 3m tall and a crossbar; elaborate artificial perches (EAPs) of 7m tall and three crossbars, and in a control area. Results showed the number of bird-dispersed seeds deposited was proportional to the number of structures for perching. The NPs also have provided other resources for birds such as food and shelter. Comparing visitation between artificial perches, there was greater use of EAPs also for having more perching structures and for being taller, providing better airspace visibility for predatory birds and tyrant-flycatchers, important seed dispersers. Thus, natural and artificial perches with similar characteristics to the EAPs are the most recommended as a base or complementary method for the restoration of degraded areas near to propagules source, also contributing to the maintenance of local fauna. PMID:26909627

  13. 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...

  14. 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.

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

    USGS Publications Warehouse

    Wells, LaRue; Jorgenson, Sherrell C.

    1983-01-01

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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Application of a data-assimilative regional ocean modeling system for assessing California Current System ocean conditions, krill, and juvenile rockfish interannual variability

    NASA Astrophysics Data System (ADS)

    Schroeder, Isaac D.; Santora, Jarrod A.; Moore, Andrew M.; Edwards, Christopher A.; Fiechter, Jerome; Hazen, Elliott L.; Bograd, Steven J.; Field, John C.; Wells, Brian K.

    2014-08-01

    To be robust and informative, marine ecosystem models and assessments require parameterized biophysical relationships that rely on realistic water column characteristics at appropriate spatial and temporal scales. We examine how hydrographic properties off California from 1990 through 2010 during late winter and spring correspond to krill and juvenile rockfish (Sebastes spp.) abundances. We evaluated coherence among temperature, salinity, depth of 26.0 potential density isopycnal, and stratification strength at regionally and monthly time scales derived from shipboard and mooring observations, and a data-assimilative Regional Ocean Model System reanalysis. The reanalysis captures spatiotemporal physical variability of coastal ocean conditions in winter and spring months and elucidates mechanisms connecting the spatial and temporal upwelling and transport dynamics on observed krill and rockfish abundances in spring. This provides evidence for a mechanistic connection between the phenology of upwelling in the California Current System and seasonal development of the shelf ecosystem.

  1. 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

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

    NASA Astrophysics Data System (ADS)

    Dieterich, Axel; Mörtl, Martin; Eckmann, Reiner

    2004-07-01

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

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

    USGS Publications Warehouse

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

    2000-01-01

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

  4. 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...

  5. 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...

  6. 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...

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

    USGS Publications Warehouse

    Kocovsky, Patrick M.; Knight, Carey T.

    2012-01-01

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

  8. 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

  9. 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.

  10. 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...

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

    USGS Publications Warehouse

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

    2012-01-01

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

  12. 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.

  13. 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.

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

    PubMed

    Moore, Joseph; Cory, Rick; Tedrake, Russ

    2014-06-01

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

  15. 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.

  16. Early osteological development of white perch and striped bass with emphasis on identification of their larvae. [Morone saxatilis; Morone americana

    SciTech Connect

    Fritzsche, R.A.; Johnson, G.D.

    1980-07-01

    A cartilage and bone straining technique was employed to study the developmental osteology of the striped bass (Morone saxatilis) and white perch (Morone americana). Special attention was given to those osteological characters that appeared to be unique to the larvae of each species. Larval striped bass and white perch exhibited diagnostic differences in the position and shape of the median ethmoid, predorsal bones, dorsal- and anal-fin pterygiophores, vertebral column, and caudal skeleton. These differences were discernible at the earliest appearance of these elements as cartilage, and allow identification of striped bass and white perch larvae above a length of about 7.5 mm.

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

    PubMed

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

    2013-01-01

    Two remedial treatments to reduce the high incidence of broken eggs in the furnished cages of our experimental layer farm were investigated: lining the nest floor with artificial turf (to increase nest acceptance) and lowering perch height (to reduce the chance of egg breakage of outside-nest eggs). A 2 × 2 factorial design was used with low (7 cm) or high (24 cm) perches, and with nest floors lined with artificial turf or plastic mesh. Eight cages, each housing 8 hens initially (aged 40 to 56 wk), were used per treatment. Egg location and percentage of broken eggs were recorded. Hen position (cage floor, nest, or perch) was recorded by direct scan-sampling observations. In addition, 8 cages (4 high + 4 low) each containing 8 hens (aged 54 to 56 wk) were videorecorded to determine perch use and behavior during the light period. Data were mainly analyzed using logistic regression and mixed models with cage as the experimental unit. Nest floor material did not influence the percentage of eggs broken or laid outside the nest. The proportion of outside-nest eggs (2.6 vs. 10.6%, P = 0.004), and consequently also of total eggs (2 vs. 4.6%, P = 0.016) broken, was lower for low than high cages. Perch use increased during the observation period, more so for the high cages during the light period and the low cages during the dark period. Perch bout duration (P < 0.001), the likelihood of ending a perching bout voluntarily (P = 0.013), and time spent sitting during perching (P = 0.007) were lower in low vs. high cages. In this study, replacing plastic mesh nest floor lining with artificial turf was not an effective remedy for the already-high rate of broken eggs, but the prevalence of broken outside-nest eggs was lower in cages with low versus high perches. However, perching behavior during the light period was more disturbed in cages with low perches. PMID:23243226

  18. 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

  19. 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.

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

    USGS Publications Warehouse

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

    2014-01-01

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

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

    PubMed

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

    2016-01-01

    This study focused on variation in fish mercury (Hg) concentrations in 185 Nile perch (Lates niloticus) samples collected across four different habitat types in Lake Nabugabo, Uganda, a tropical lake located proximate to Lake Victoria. We quantified the stomach contents of Nile perch using the % index of relative importance, as well as, nitrogen and carbon isotopic concentrations to assess the role of diet and trophic level on Hg concentrations. In each habitat, we also evaluated a suite of chemical and physical characteristics that are commonly associated with variation in Hg bioavailability in temperate systems. Using linear mixed models and ANOVA, we demonstrate that habitat of capture is an important predictor of Hg concentrations in Nile perch from Lake Nabugabo and that the relationship between habitat and Hg is size and diet dependent. Nile perch diet as well as dissolved oxygen concentration and pH were also correlated with observed differences in fish Hg. Overall, Hg concentrations in Nile perch were all well below the WHO/FAO recommended guideline of 500 ng/g (mean 13.6 ± 0.4 ng/g wet weight; range 4.9 and 29.3 ng/g wet weight). This work contributes to a growing awareness of intra-lake divergence in Nile perch, as well as, divergence in Hg concentrations between varying aquatic habitat types, particularly wetlands. PMID:26520435

  2. 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.

  3. 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.

  4. 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

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

    USGS Publications Warehouse

    Mraz, Donald

    1952-01-01

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

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

    PubMed

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

    2015-11-01

    A positive relationship was observed between Secchi disc depth and dermal melanin concentration in yellow perch Perca flavescens sampled from 11 humic lakes located on the Canadian Shield in southern Quebec (Canada). Secchi disc depth explained 23% of the variations of dermal melanin concentration. Secchi disc depth and thus water transparency appear to have a positive influence on melanin production in the dermis of P. flavescens. PMID:26399476

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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

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

    PubMed

    Polet, D T; Rival, D E

    2015-10-26

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

  13. 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.

  14. 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.

  15. Baseline risk assessment of the perched water system at the INEL test reactor area

    SciTech Connect

    Gordon, J.W.; Sinton, P.O. ); Jensen, N. ); McCormick, S. )

    1993-01-01

    A baseline health risk assessment (HRA) was prepared to evaluate potential risks to human health and the environment posed by the Perched Water System (PWS) at the Test Reactor Area (TRA). The PWS has been designated Operable Unit 2-12, one of the 13 operable units identified at TRA. During the period from 1962 to 1990, a total of 6770 million gal of water were discharged from the TRA to unlined surface ponds. Wastewater discharged to the surface ponds at TRA percolates downward through the surficial alluvium and the underlying basalt bedrock. A resulting shallow perched water zone has formed at the interface between the surficial sediments and the underlying basalt. Further downward movement of groundwater is again impeded by a low-permeability layer of silt, clay, and sand encountered at a depth of [approximately]150 ft. The deep perched water zone occurs on top of this low-permeability interbed. An evaluation was made as to whether potential risks for the PWS could justify implementing a remedial action. The risk evaluation consisted of two parts, the human health evaluation and the ecological evaluation.

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

    PubMed

    Polet, D T; Rival, D E

    2015-12-01

    Rapid pitch-up has been highlighted as a mechanism to generate large lift and drag during landing manoeuvres. However, pitching rates had not been measured previously in perching birds, and so the direct applicability of computations and experiments to observed behaviour was not known. We measure pitch rates in a small, wild bird (the black-capped chickadee; Poecile atricapillus), and show that these rates are within the parameter range used in experiments. Pitching rates were characterized by the shape change number, a metric comparing the rate of frontal area increase to acceleration. Black-capped chickadees increase the shape change number during perching in direct proportion to their total kinetic and potential energy at the start of the manoeuvre. The linear relationship between dissipated energy and shape change number is in accordance with a simple analytical model developed for two-dimensional pitching and decelerating airfoils. Black-capped chickadees use a wing pitch-up manoeuvre during perching to dissipate energy quickly while maintaining lift and drag through rapid area change. It is suggested that similar pitch-and-decelerate manoeuvres could be used to aid in the controlled, precise landings of small manoeuvrable air vehicles. PMID:26502303

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

    USGS Publications Warehouse

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

    1980-01-01

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

  18. 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.

  19. 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.

  20. Experimental manipulations of tissue oxygen supply do not affect warming tolerance of European perch.

    PubMed

    Brijs, Jeroen; Jutfelt, Fredrik; Clark, Timothy D; Gräns, Albin; Ekström, Andreas; Sandblom, Erik

    2015-08-01

    A progressive inability of the cardiorespiratory system to maintain systemic oxygen supply at elevated temperatures has been suggested to reduce aerobic scope and the upper thermal limit of aquatic ectotherms. However, few studies have directly investigated the dependence of thermal limits on oxygen transport capacity. By manipulating oxygen availability (via environmental hyperoxia) and blood oxygen carrying capacity (via experimentally induced anaemia) in European perch (Perca fluviatilis Linneaus), we investigated the effects of oxygen transport capacity on aerobic scope and the critical thermal maximum (CT(max)). Hyperoxia resulted in a twofold increase in aerobic scope at the control temperature of 23°C, but this did not translate to an elevated CT(max) in comparison with control fish (34.6±0.1 versus 34.0±0.5°C, respectively). Anaemia (∼43% reduction in haemoglobin concentration) did not cause a reduction in aerobic scope or CT(max) (33.8±0.3°C) compared with control fish. Additionally, oxygen consumption rates of anaemic perch during thermal ramping increased in a similar exponential manner to that in control fish, highlighting that perch have an impressive capacity to compensate for a substantial reduction in blood oxygen carrying capacity. Taken together, these results indicate that oxygen limitation is not a universal mechanism determining the CT(max) of fishes.

  1. 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

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

    PubMed

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

    2015-01-01

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

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

    PubMed

    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

  4. 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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

    Cooper, William E

    2010-12-01

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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Oxidative stress, neurotoxicity, and metallothionein (MT) gene expression in juvenile rock fish Sebastes schlegelii under the different levels of dietary chromium (Cr(6+)) exposure.

    PubMed

    Kim, Jun-Hwan; Kang, Ju-Chan

    2016-03-01

    Juvenile Sebastes schlegelii were exposed for 4 weeks with the different levels of dietary chromium (Cr(6+)) concentration (0, 30, 60, 120 and 200mg/kg). The superoxide dismutase (SOD) activity, glutathione S-transferase (GST) activity, and glutathione (GSH) level of liver and gill were evaluated after 4 weeks exposure. The SOD and GST activity of liver and gill was significantly increased in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks, whereas a considerable decrease in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks was observed in the GSH levels of liver and gill. In neurotoxicity, AChE activity was significatly inhibited in brain in the concentration of 240mg/kg after 2 weeks and over 60mg/kg after 4 weeks and muscle in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks. Metallothionein (MT) gene in liver was considerably increased over 120mg/kg after 2 weeks and at 30, 120, and 240mg/kg after 4 weeks by dietary chromium exposure. The results indicate that dietary Cr exposure over 120mg/kg can induce substantial alterations in antioxidant responses, AChE activity and MT gene expression.

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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).

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. Residue depletion of albendazole and its metabolites in aquacultured yellow perch (Perca flavescens).

    PubMed

    Yu, D; Evans, E R; Hasbrouck, N; Reimschuessel, R; Shaikh, B

    2012-12-01

    Metabolism and residue depletion studies are conducted to determine the marker residue (MR) of a drug in a target tissue of food animals. The MR is used to monitor potential unauthorized use of drugs. The current work is a continuation of our efforts to study metabolism and depletion profiles of albendazole in multiple finfish species to determine a common MR. The results of this study suggest that albendazole sulfone metabolite could potentially serve as MR for albendazole in yellow perch muscle, similar to channel catfish and hybrid striped bass as reported previously by us. PMID:22150530

  7. 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

  8. 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...

  9. 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.

  10. 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

  11. 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.

  12. 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.

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

    PubMed

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

    2012-11-01

    Arboreal habitats pose several challenges for locomotion resulting from narrow cylindrical surfaces, steep slopes, and secondary branches that can form obstructions. We used laboratory trials to test whether different diameters, slopes, or complexity of branches affected maximum speeds and perch choice of the semi-arboreal white-footed mouse (Peromyscus leucopus). We tested locomotor performance of mice running horizontally and up and down 45° slopes for cylindrical artificial branches with five diameters ranging from 10 to 116 mm and on a subset of diameters for cylinders that were horizontal and had pegs (e.g., secondary branches) every 10 or 20 cm. Slope, diameter, and presence of pegs on top of cylinders had significant and interactive effects on locomotor performance. On horizontal cylinders the speed of mice increased with increased diameter among the three smallest diameters, but changed little with further increases in diameter, whereas for sloped surfaces the extreme diameters had lower speeds than an intermediate diameter. For a given diameter, the speeds of mice were usually faster when running horizontally rather than running uphill or downhill. The presence of pegs greatly decreased running speed compared to unobstructed surfaces, but the magnitude of this effect decreased as diameter increased. The difficulties of maintaining balance and avoiding toppling may have caused much of the decrease in speed and associated increased amounts of pausing. Only 1 of 11 choice tests detected a significant bias of mice favoring the perch that maximized locomotor performance. PMID:22927206

  14. 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.

  15. 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.

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

    PubMed

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

    2012-11-01

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

  17. 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.

  18. 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

  19. Estimating ground water recharge using flow models of perched karstic aquifers.

    PubMed

    Weiss, Menachem; Gvirtzman, Haim

    2007-01-01

    The fraction of rain that is annually recharged to ground water is a function of the transient quantities of precipitation (wet vs. dry years) as well as other meteorological and geologic factors, and thus it is very difficult to estimate. In this study, we have used long records (20 to 30 years) of precipitation and spring discharge to reconstruct the transient character of yearly recharge. These data sets were used to calibrate numerical ground water flow models on the less than 3 km(2) scale for four separate perched karstic aquifers in the Judean and Samarian Mountains of Israel. The stratification and karstic character of the local carbonate rock aquifers cause ground water to flow through discrete dissolution channels and to discharge at isolated springs. An innovative, dual-porosity approach was used where a finite-difference solution simulates flow in the rock matrix, while the karstic channels are simulated using computationally simple drains. Perched conditions are also simulated innovatively using MODFLOW by treating the bottom unsaturated layer as if it is saturated, but by assuming zero pressure head throughout the "unsaturated" layer. Best fitting between measured and computed spring hydrograph data has allowed us to develop a set of empirical functions relating measured precipitation to recharge to the aquifer. The generic methodology presented gives insight into the suspected changes in aquifer recharge rates between particularly wet or dry years.

  20. Behavioural strategy of large perch Perca fluviatilis varies between a mesotrophic and a hypereutrophic lake.

    PubMed

    Jacobsen, L; Berg, S; Baktoft, H; Skov, C

    2015-03-01

    Behaviour of large perch Perca fluviatilis was studied in two lakes differing in environmental state i.e. mesotrophic v. hypereutrophic. A total of 20 adult perch P. fluviatilis (29-42 cm total length) in each lake were tagged with radio-transmitters, tracked and located eight times a day during six 24 h tracking periods over a year, enabling detection of differences in diel activity patterns and habitat use during summer and winter under two different environmental regimes. During summer, P. fluviatilis in the mesotrophic lake showed a distinct crepuscular activity pattern and a change from pelagic residency during daytime towards the littoral zone at night. In contrast, P. fluviatilis in the hypereutrophic lake were active during the entire diel cycle and were spread throughout the lake also during dark. During winter, crepuscular patterns of activity were seen in both lakes. Condition factor of large P. fluviatilis did not differ between the two lakes. Thus, it is suggested that P. fluviatilis in the hypereutrophic turbid lake adopted an alternative behaviour for successful foraging, being uniformly active throughout the diel cycle.

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

    USGS Publications Warehouse

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

    2012-01-01

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

  2. 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

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

    USGS Publications Warehouse

    Patrick, Matthew R.; Orr, Tim R.

    2012-01-01

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

  4. Molecular characterization and expression analysis of mitochondrial antiviral signaling protein gene in sea perch, Lateolabrax japonicus.

    PubMed

    Jia, Peng; Jin, Yilin; Chen, Limin; Zhang, Jing; Jia, Kuntong; Yi, Meisheng

    2016-02-01

    The mitochondrial antiviral signaling protein (MAVS) is vital for host defenses against viral infection by inducing expression of type I interferon. Here, the MAVS of sea perch (Lateolabrax japonicus) (LjMAVS) was cloned and analyzed. The complete cDNA sequence of LjMAVS was 3207 bp and encoded a polypeptide of 601 amino acids. LjMAVS contains an N-terminal CARD-like domain, a central proline-rich domain and a C-terminal transmembrane domain. Phylogenetic analysis indicated that LjMAVS exhibited the closest relationship to O. fasciatus MAVS. LjMAVS was ubiquitously expressed in all tested tissues of healthy fish. The expression of LjMAVS was significantly increased post nervous necrosis virus (NNV) infection in vivo in all the selected tissues. Furthermore, time course analysis showed that LjMAVS transcripts significantly increased in the brain, spleen and kidney tissues after NNV infection. LjMAVS mRNA expression was significantly up-regulated in vitro after poly I:C stimulation. The viral gene transcription of RGNNV was significantly decreased in LjMAVS over-expressing LJB cells. These findings provide useful information for further elucidating the function ofLjMAVS in antiviral innate immune against NNV in sea perch.

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

    PubMed

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

    2012-11-01

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

  6. 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.

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

    PubMed

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

    2015-05-01

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

  8. Ocean tides

    NASA Technical Reports Server (NTRS)

    Hendershott, M. C.

    1975-01-01

    A review of recent developments in the study of ocean tides and related phenomena is presented. Topics briefly discussed include: the mechanism by which tidal dissipation occurs; continental shelf, marginal sea, and baroclinic tides; estimation of the amount of energy stored in the tide; the distribution of energy over the ocean; the resonant frequencies and Q factors of oceanic normal modes; the relationship of earth tides and ocean tides; and numerical global tidal models.

  9. 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...

  10. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  14. 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

  15. 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.

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

    PubMed

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  18. Caesium-137 in Perch in Swedish Lakes after Chernobyl-present situation, relationships and trends.

    PubMed

    Håkanson, L; Andersson, T; Nilsson, A

    1989-01-01

    The Chernobyl accident, and the general acidification of Swedish water systems, form the base for this project. The aims of the work have been to present results on the linkage between the concentration of Cs-137 in fish, lake load of Cs and lake characteristics, to give a preliminary prognosis on the recovery, and to put the results within a wider framework of environmental hazard analysis. A broad set of data on limnology, morphometry and drainage area conditions from 41 lakes were collected during 1986 and 1987. Cs-137 was determined in 1 + perch (Cs-pe, 1-year-old perch), water, material collected by sediment traps and from surficial sediments. The main results are as follows. The average value of Cs-pe for all lakes has dropped from 9800 Bq kg(-1) (wet) to 5040 between the 2 years. Generally, the decrease is between 5 and 90%. We have tested if any factor(s) could be specifically linked to this decrease-no such factors have been found. The concentrations of Cs in sediment traps have, on average, decreased by 80%. Very high correlations exist between Cs-pe and the caesium load as determined from the sediment traps. Between 1 and 10% (mean 3.9%) of the initial fall-out deposition to the drainage area was transported from land to water during June to August 1986. The variation in initial fall-out deposition explains 65-69% of the variability in Cs-pe; the degree of explanation (= coefficient of determination, r2) increases to about 85% if one also takes into account the lake water hardness and totP. A map showing with lakes likely to have 1 + perch with higher mean Cs-concentrations than 1500 Bq kg(-1) wet is presented. Between 4000 and 7000 lakes in Sweden appear to have Cs-pe higher than 1500 Bq kg(-1) wet, figures which emphasize the serious impact of the Chernobyl accident on the environmental conditions in Sweden.

  19. The influence of providing perches and string on activity levels, fearfulness and leg health in commercial broiler chickens.

    PubMed

    Bailie, C L; O'Connell, N E

    2015-04-01

    The aim of this study was to assess the effect of providing environmental enrichment in the form of perches and string on the behaviour and welfare of commercial broiler chickens. Houses containing ~23 000 broiler chickens were assigned to one of four treatments in a 2×2 factorial design. Treatments involved two levels of access to perches (P) (present (24/house) '+P' or absent '-P') and two levels of access to string (S) (present (24/house) '+S' or absent '-S'). All houses contained windows, and 30 straw bales were provided from day 10 of the rearing cycle. Treatments were applied in one of four houses on a single farm, and were replicated over four production cycles. Behaviour and leg health were observed in weeks 3 to 5 of the rearing cycle. Production performance and environmental parameters were also measured. There was an interaction between perches and age in the percentage of birds observed lying, with higher percentages of birds observed lying in the +P treatment than in the -P treatment during weeks 4 and 5. There was also a significant interaction between string and age in the percentage of birds observed in locomotion, with higher percentages observed in locomotion in the -S treatment than in the +S treatment during weeks 4 and 5. There was also an interaction between string and age in average gait scores, with lower gait scores in the +S treatment than in the -S treatment during weeks 3 and 5 but not within week 4. Daytime observations showed that perches and strings were used frequently, with one bout of perching occurring approximately every 80 s/perch, and one bout of pecking at string occurring every 78 s/string on average. There was a significant effect of age on use of perches (P<0.001) and string (P<0.001), with perching peaking during week 5 and string pecking peaking during week 3. We conclude that commercial broilers in windowed houses with access to straw bales display an interest in additional enrichment stimuli in the form of perches and

  20. The influence of providing perches and string on activity levels, fearfulness and leg health in commercial broiler chickens.

    PubMed

    Bailie, C L; O'Connell, N E

    2015-04-01

    The aim of this study was to assess the effect of providing environmental enrichment in the form of perches and string on the behaviour and welfare of commercial broiler chickens. Houses containing ~23 000 broiler chickens were assigned to one of four treatments in a 2×2 factorial design. Treatments involved two levels of access to perches (P) (present (24/house) '+P' or absent '-P') and two levels of access to string (S) (present (24/house) '+S' or absent '-S'). All houses contained windows, and 30 straw bales were provided from day 10 of the rearing cycle. Treatments were applied in one of four houses on a single farm, and were replicated over four production cycles. Behaviour and leg health were observed in weeks 3 to 5 of the rearing cycle. Production performance and environmental parameters were also measured. There was an interaction between perches and age in the percentage of birds observed lying, with higher percentages of birds observed lying in the +P treatment than in the -P treatment during weeks 4 and 5. There was also a significant interaction between string and age in the percentage of birds observed in locomotion, with higher percentages observed in locomotion in the -S treatment than in the +S treatment during weeks 4 and 5. There was also an interaction between string and age in average gait scores, with lower gait scores in the +S treatment than in the -S treatment during weeks 3 and 5 but not within week 4. Daytime observations showed that perches and strings were used frequently, with one bout of perching occurring approximately every 80 s/perch, and one bout of pecking at string occurring every 78 s/string on average. There was a significant effect of age on use of perches (P<0.001) and string (P<0.001), with perching peaking during week 5 and string pecking peaking during week 3. We conclude that commercial broilers in windowed houses with access to straw bales display an interest in additional enrichment stimuli in the form of perches and

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

    USGS Publications Warehouse

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

    2009-01-01

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

  2. 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

    ... BSAI (77 FR 10669, February 23, 2012). In accordance with Sec. 679.20(d)(1)(iii), the Regional... for Fisheries, NOAA, (AA) finds good cause to waive the requirement to provide prior notice and... data only became available as of June 5, 2012. The AA also finds good cause to waive the 30-day...

  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

    ... BSAI (77 FR 10669, February 23, 2012). In accordance with Sec. 679.20(d)(1)(iii), the Regional... for Fisheries, NOAA, (AA) finds good cause to waive the requirement to provide prior notice and... data only became available as of June 27, 2012. The AA also finds good cause to waive the 30-day...

  4. 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

    ... groundfish of the (78 FR 13162, February 26, 2013). In accordance with Sec. 679.20(d)(1)(i), the... Administrator for Fisheries, NOAA (AA), finds good cause to waive the requirement to provide prior notice and... because the most recent, relevant data only became available as of June 26, 2013. The AA also finds...

  5. 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

    ... BSAI (76 FR 11139, March 1, 2011). In accordance with Sec. 679.20(d)(1)(iii), the Regional... Fisheries, NOAA, (AA) finds good cause to waive the requirement to provide prior notice and opportunity for... AA also finds good cause to waive the 30-day delay in the effective date of this action under 5...

  6. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE... Administration (NOAA), Commerce. ACTION: Temporary rule; modification of a closure. SUMMARY: NMFS is opening... comments via the Federal e-Rulemaking Portal. Go to www.regulations.gov/#!docketDetail...

  7. Old moms with new tricks: modeling the effects of age-specific spawning behaviors in Pacific Ocean perch

    EPA Science Inventory

    In commercially exploited, long-lived fish species, age structure plays an important role in determining population stability and resilience to human and environmental impacts. The often observed increase in energy allocation per offspring by older females can improve larval surv...

  8. 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

    ... final 2011 and 2012 harvest specifications for groundfish of the BSAI (76 FR 11139, March 1, 2011). In... specifications for groundfish in the BSAI (76 FR 11139, March 1, 2011). The harvest specification for the 2011... fisheries data in a timely fashion and would delay the apportionment of the non-specified reserves...

  9. Impact of Toxic Cyanobacterial Blooms on Eurasian Perch (Perca fluviatilis): Experimental Study and In Situ Observations in a Peri-Alpine Lake

    PubMed Central

    Sotton, Benoît; Guillard, Jean; Bony, Sylvie; Devaux, Alain; Domaizon, Isabelle; Givaudan, Nicolas; Crespeau, François; Huet, Hélène; Anneville, Orlane

    2012-01-01

    Due to the importance of young-of-the-year (YOY) perch in the peri-alpine regions where they are consumed, the microcystin (MC) contamination of YOY perch was analysed both in field (Lake Bourget, France) and experimentally using force-feeding protocols with pure MCs. In-situ, schools of YOY perch present in the epilimnion of the lake were never found in direct contact with the P. rubescens blooms that were present in the metalimnion. However, MCs were detected in the muscles and liver of the fish and were thus assumed to reach YOY perch through dietary routes, particularly via the consumption of MC-containing Daphnia. Force-feeding experiment demonstrates the existence of MC detoxification/excretion processes and suggests that in situ, YOY perch could partly detoxify and excrete ingested MCs, thereby limiting the potential negative effects on perch populations under bloom conditions. However, because of chronic exposure these processes could not allow for the complete elimination of MCs. In both experimental and in situ studies, no histological change was observed in YOY perch, indicating that MC concentrations that occurred in Lake Bourget in 2009 were too low to cause histological damage prone to induce mortality. However, Deoxyribonucleic acid (DNA) damages were observed for both the high and low experimental MC doses, suggesting that similar effects could occur in situ and potentially result in perch population disturbance during cyanobacterial blooms. Our results indicate the presence of MCs in wild perch, the consumption of this species coming from Lake Bourget is not contested but more analyses are needed to quantify the risk. PMID:23272228

  10. Uptake and elimination of {sup 137}Cs by climbing perch (Anabus testudineus)

    SciTech Connect

    Malek, M.A.

    1999-12-01

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

  11. Parameterization of European perch Perca fluviatilis length-at-age data using stochastic Gompertz growth models.

    PubMed

    Troynikov, V S; Gorfine, H K; Ložys, L; Pūtys, Z; Jakubavičiūtė, E; Day, R W

    2011-12-01

    Three stochastic versions of the Gompertz growth model were used to parameterize total length (L(T) )-at-age data for perch Perca fluviatilis, an important target species for commercial and recreational fishers and a food species for predatory fishes and aquatic birds. Each model addresses growth heterogeneity by incorporating random parameters from a specific positive distribution: Weibull, gamma or log-normal. The modelling outputs for each version of the model provide L(T) distributions for selected ages and percentiles of L(T) at age for both males and females. The results highlight the importance of using a stochastic approach and the logistic-like growth pattern for analysing growth data for P. fluviatilis in Curonian Lagoon (Lithuania). Outputs from this modelling can be extended to a stochastic analysis of fish cohort dynamics, incorporating all length-based biological relationships, and the selectivity-related interactions between fish cohorts and fishing gear.

  12. Hawk Eyes II: Diurnal Raptors Differ in Head Movement Strategies When Scanning from Perches

    PubMed Central

    O'Rourke, Colleen T.; Pitlik, Todd; Hoover, Melissa; Fernández-Juricic, Esteban

    2010-01-01

    Background Relatively little is known about the degree of inter-specific variability in visual scanning strategies in species with laterally placed eyes (e.g., birds). This is relevant because many species detect prey while perching; therefore, head movement behavior may be an indicator of prey detection rate, a central parameter in foraging models. We studied head movement strategies in three diurnal raptors belonging to the Accipitridae and Falconidae families. Methodology/Principal Findings We used behavioral recording of individuals under field and captive conditions to calculate the rate of two types of head movements and the interval between consecutive head movements. Cooper's Hawks had the highest rate of regular head movements, which can facilitate tracking prey items in the visually cluttered environment they inhabit (e.g., forested habitats). On the other hand, Red-tailed Hawks showed long intervals between consecutive head movements, which is consistent with prey searching in less visually obstructed environments (e.g., open habitats) and with detecting prey movement from a distance with their central foveae. Finally, American Kestrels have the highest rates of translational head movements (vertical or frontal displacements of the head keeping the bill in the same direction), which have been associated with depth perception through motion parallax. Higher translational head movement rates may be a strategy to compensate for the reduced degree of eye movement of this species. Conclusions Cooper's Hawks, Red-tailed Hawks, and American Kestrels use both regular and translational head movements, but to different extents. We conclude that these diurnal raptors have species-specific strategies to gather visual information while perching. These strategies may optimize prey search and detection with different visual systems in habitat types with different degrees of visual obstruction. PMID:20877650

  13. Identification and characterization of the melanoma differentiation - associated gene 5 in sea perch, Lateolabrax japonicus.

    PubMed

    Jia, Peng; Jia, Kuntong; Chen, Limin; Le, Yao; Jin, Yilin; Zhang, Jing; Zhu, Limei; Zhang, Li; Yi, Meisheng

    2016-08-01

    The RIG-I-like receptors family is a group of cytosolic RNA helicase proteins that can recognize viral RNA via binding to pathogen associated molecular pattern motifs within RNA ligands. A novel vertebrate RLR counterpart named LjMDA5 was firstly identified from the marine fish sea perch Lateolabrax japonicus in this study. The full-length cDNA of LjMDA5 is 3750 bp and encodes a polypeptide of 988 amino acids, containing two N-terminal tandem caspase activation and recruitment domains, a DExH (Asp-Glu-X-His) box domain, an HELICc domain, and a C-terminal domain RIG-I. Phylogenetic analysis showed that LjMDA5 shared the closest genetic relationship with the MDA5 of Larimichthys crocea. Quantitative RT-PCR analysis showed that LjMDA5 was ubiquitously expressed and up-regulated significantly in all selected tissues in vivo post NNV infection. Time course analysis showed that LjMDA5 transcripts significantly increased in spleen and kidney. We found LjMDA5 could be regulated in the sea perch LJB and LJF cell lines after lipopolysaccharide, polyinosinic-polycytidylic acid treatment and NNV challenge. RNA interference experiment indicated that silencing of LjMDA5 significantly increased RGNNV replication and virus production in NNV infected LJF cells. Our results revealed that MDA5 was essential for host defense against NNV, which provided new insights into the function of RLR signaling pathway during NNV infection in fish.

  14. High summer concentrations of mercury in big perch (Perca fluviatilis L) from the Tvärminne archipelago (SW Finland) and Nåtö (Aland Islands) Baltic sea.

    PubMed

    Voigt, H R

    2001-04-01

    During high summer seasons in 1994-1999 84 big (20-42 cm total length) female perch (Perca fluviatilis L) were sampled from the waters around Tvärminne Zoological Station on the Hanko-Hangö peninsula on the SW coast of Finland for mercury analysis. Additional sampling of 13 big female perch during the same season were carried out from the waters of Nåtö Biological Station on the Aland Islands in 1997-1998. High summer is the most important season for perch fishing and consumption not only for private families during leisure time but also for professional fishery including trade and export, processing and preparations for restaurants. Fillets of big specimen of perch, s.c. "fillet perch" or "sea perch" from outer coastal waters were chosen for the study to find out the levels of mercury concentration in these desirable fish. The mean concentration of mercury in the dorsal muscle tissue (fillet) of big female "sea perch" from the coastal waters of Tvärminne Zoological Station was calculated to 0.22 (SD 0.08), range 0.08-0.43 mg/kg, f wt and for big female perch from the waters of Nåtö Biological Station to 0.18 (SD 0.07), range 0.07-0.30 mg/kg, f wt respectively. The results show a considerably lower mercury level in big "fillet perch" caught from the outer coastal waters in both Finland (and Estonia) compared with the levels recorded of big "fillet perch" from fresh water lakes and reservoirs. Thus, the common expression "sea perch" may also be used in the form "Baltic sea perch" meaning big healthy perch with low concentrations of mercury and caught from the outer coastal waters in S and SW Finland (and W Estonia) when marketing perch for human consumption.

  15. The Optimum Feeding Frequency in Growing Korean Rockfish (Sebastes schlegeli) Rearing at the Temperature of 15°C and 19°C

    PubMed Central

    Mizanur, Rahman Md; Bai, Sungchul C

    2014-01-01

    Two feeding trials were conducted to determine the optimum feeding frequency in growing Korean rockfish, (Sebastes schlegeli) reared at the temperatures of 15°C and 19°C. Fish averaging 92.2±0.7 g (mean±standard deviation [SD]) at 15.0±0.5°C and 100.2±0.4 g (mean±SD) at 19.0±0.5°C water temperature were randomly distributed into each of 15 indoor tanks containing 250-L sea water from a semi-recirculation system. A total of five feeding frequency groups were set up in three replicates as follows: one meal in a day at 08:00 hour, two meals a day at 08:00 and 17:00 hours, three meals a day at 08:00, 14:00, and 20:00 hours, four meals a day at 08:00, 12:00, 16:00, and 20:00 hours, and one meal every 2 days at 08:00 hour. Fish were fed at the rate of 1.2% body weight (BW)/d at 15°C and 1.5% BW/d at 19°C. At the end of 8 wks of feeding trial weight gain and specific growth rate were significantly higher at the fish fed groups of one meal a day and two meals a day at 15°C and fish fed groups of 1 meal every 2 days at 19°C were significantly lower than those of all other fish fed groups. Glutamic oxaloacetic transaminase and glutamic pyruvic transaminase of fish fed group at 1 meal every 2 days was significantly higher than those of all other fish fed groups in both experiments. Weight gain, specific growth rate and condition factor were gradually decreased as the feeding frequency increased. The results indicate that growing Korean rockfish 92 and 100 g perform better at 15°C than 19°C water temperature. As we expected, current results have indicated that a feeding frequency of 1 meal a day is optimal for the improvement of weight gain in growing Korean rockfish grown from 92 g to 133 g at 15°C and 100 g to 132 g at 19°C water temperature. PMID:25178376

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

    PubMed

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

    2015-12-01

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

  17. 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

  18. Onset of a perched water table during infiltration in a gradually layered soil: Reanalysis of a laboratory experiment

    NASA Astrophysics Data System (ADS)

    Barontini, Stefano; Grottolo, Maria; Belluardo, Giorgio; Bacchi, Baldassare; Ranzi, Roberto

    2014-05-01

    Perched water tables in the upper soil layers play a key role in water partitioning during infiltration. They are typically thin and ephemeral, and onset in soils where a decrease of hydraulic conductivity and diffusivity is observed with depth. Aiming at better understanding their dynamics, we theoretically and numerically reanalysed a laboratory experiment, during which the onset of a perched water table was observed in a reconstructed soil with gradually decreasing conductivity at saturation with depth. The laboratory prototype was a prismatic column filled with 9 different 0.1 m--deep soil layers. The grain--size distribution curve and porosity of the layers were designed in order to reproduce an exponential decay of conductivity, on the basis of the application of a modified Kozeny--Carman relationship. During the experiment the soil was artificially wetted by means of a rainfall simulator at a rate previously determined in order to maintain a constant water content on the surface for 9 hours. Istantaneous volumetric water content profiles were measured by means of 9 multiplexed TDR probes. As a result of the experiment a water content peak was observed below the soil surface. Then it emphasised and moved downward until a perched water table formed at an intermediate height in the column, about 6 h after the beginning of the experiment. The thickness of the perched water table rapidly increased upward while the wetting front slowly travelled downward. The observed patterns supported phenomenological aspects enlightened by an analytical solution of transient infiltration in a gradually layered soil and by a numerical solution of similar cases. When the perched water table onset, the infiltration was quantitatively compatible with the presence of a perched water table within the soil column, on the basis of a steady infiltration theoretical framework. Then a reanalysis of the experiment was performed by numerically solving the Richards equation for a

  19. Ocean Acidification

    NASA Astrophysics Data System (ADS)

    Iglesias-Rodriguez, Maria Debora

    The oceans play a central role in the maintenance of life on Earth. Oceans provide extensive ecosystems for marine animals and plants covering two-thirds of the Earth's surface, are essential sources of food, economic activity, and biodiversity, and are central to the global biogeochemical cycles. The oceans are the largest reservoir of carbon in the Planet, and absorb approximately one-third of the carbon emissions that are released to the Earth's atmosphere as a result of human activities. Since the beginning of industrialization, humans have been responsible for the increase in one greenhouse gas, carbon dioxide (CO2), from approximately 280 parts per million (ppm) at the end of the nineteenth century to the current levels of 390ppm. As well as affecting the surface ocean pH, and the organisms living at the ocean surface, these increases in CO2 are causing global mean surface temperatures to rise.

  20. Age, growth, spawning season, and fecundity of the trout-perch (Percopsis omiscomaycus) in southeastern Lake Michigan

    USGS Publications Warehouse

    House, Robert; Wells, LaRue

    1973-01-01

    Growth of trout-perch (Percopsis omiscomaycus) in the first 2 years of life was somewhat slower in southeastern Lake Michigan (average length at end of second year, 83 mm) than in Lower Red Lake, Minnesota (90 mm), but considerably faster than in Lake Superior (58 mm); size differences in later years were slightly less pronounced. Young fish began growing earlier in the year (some before June 20) than older ones (as late as August). Females tended to live longer than males, as they do in Lower Red Lake and Lake Superior. Trout-perch spawned from late June or early July until late September, somewhat later than in Lower Red Lake (May to August) or Lake Erie (June to August). Fecundity was similar to that in Lake Erie; mature females 94-146 mm long contained from 126 to 1329 yolked eggs.

  1. Reduction in recruitment of white bass in Lake Erie after invasion of white perch

    USGS Publications Warehouse

    Madenjian, Charles P.; Knight, Roger L.; Bur, Michael; Forney, John L.

    2000-01-01

    Recruitment to the adult population of white bass Morone chrysops in Lake Erie sharply declined during the early 1980s. To explain this phenomenon, we formulated the following four hypotheses: (1) the biological characteristics of adult spawners changed during the early 1980s, so that the ability to produce eggs decreased; (2) the decrease in phosphorus loadings to Lake Erie during the 1970s resulted in a lower abundance of crustacean zooplankton and thus in reduced survival of age-0 white bass; (3) the increase in the population of adult walleyes Stizostedion vitreum in Lake Erie during the 1970s and 1980s led to reduced survival of age-0 white bass; and (4) establishment of the white perch Morone americana population in Lake Erie during the early 1980s led to reduced survival of the early life stages of white bass. The growth, maturity, and fecundity of adults during the period 1981-1997 were compared with the same characteristics found by earlier studies. The mean length, weight, and condition factors that we calculated were higher than those reported for Lake Erie in 1927-1929 for all age groups examined, and white bass in Lake Erie matured at an earlier age during 1981-1997 than during 1927-1929. Fecundity estimates ranged from 128,897 to 1,049,207 eggs/female and were similar to estimates from other populations. Therefore, the first hypothesis was rejected. With respect to the second hypothesis, zooplankton surveys conducted during 1970 and 1983-1987 indicated that the abundance of crustacean zooplankton in Lake Erie did not change between the two time periods. However, these results were not conclusive because only a single-year survey was conducted before 1980. Based on walleye diet studies and estimates of walleye population size, walleye predation pressure on age-0 white bass in Lake Erie during 1986-1988 was just slightly higher than that during 1979-1981. Thus, such pressure can explain only a minor portion of the reduction in white bass recruitment. To

  2. Perching of Tengmalm's owl (Aegolius funereus) nestlings at the nest box entrance: effect of time of the day, age, wing length and body weight.

    PubMed

    Kouba, Marek; Bartoš, Luděk; Zárybnická, Markéta

    2014-01-01

    The behaviour of the nestlings of nocturnal cavity-nesting species has relatively rarely been studied in detail because of problems connected with use of the technical devices required to provide long-term monitoring of individuals. However, long-term observation of nestling behaviour is crucial in order to identify different types of behaviour which may be caused by sibling competition at the end of nesting period. We studied behaviour of 43 Tengmalm's owl (Aegolius funereus) nestlings at 14 nests using a camera and a chip system. The nestlings perched at the nest box entrance from an average age of 28 days from hatching (range 24-34 days) until fledging, spending around 2 hours per day here in total, in periods ranging from a few seconds to 147 min (7.6±10.9 min, mean ± SD). We found that individual duration of perching at the nest box entrance was significantly influenced by nestlings' age and wing length and that the duration of perching at the nest box entrance significantly decreased with time of night. However, during daylight hours, time of day had no effect on either probability or duration of nestlings' perching. We suggest daylight perching at the nest box entrance results from nestlings' preparation for fledging, while individuals perching here during the night may gain an advantageous position for obtaining food from the parents; another possibility at all times of day is that nestlings can reaffirm their social dominance status by monopolizing the nest box entrance.

  3. Perching of Tengmalm's Owl (Aegolius funereus) Nestlings at the Nest Box Entrance: Effect of Time of the Day, Age, Wing Length and Body Weight

    PubMed Central

    Kouba, Marek; Bartoš, Luděk; Zárybnická, Markéta

    2014-01-01

    The behaviour of the nestlings of nocturnal cavity-nesting species has relatively rarely been studied in detail because of problems connected with use of the technical devices required to provide long-term monitoring of individuals. However, long-term observation of nestling behaviour is crucial in order to identify different types of behaviour which may be caused by sibling competition at the end of nesting period. We studied behaviour of 43 Tengmalm's owl (Aegolius funereus) nestlings at 14 nests using a camera and a chip system. The nestlings perched at the nest box entrance from an average age of 28 days from hatching (range 24–34 days) until fledging, spending around 2 hours per day here in total, in periods ranging from a few seconds to 147 min (7.6±10.9 min, mean ± SD). We found that individual duration of perching at the nest box entrance was significantly influenced by nestlings' age and wing length and that the duration of perching at the nest box entrance significantly decreased with time of night. However, during daylight hours, time of day had no effect on either probability or duration of nestlings' perching. We suggest daylight perching at the nest box entrance results from nestlings' preparation for fledging, while individuals perching here during the night may gain an advantageous position for obtaining food from the parents; another possibility at all times of day is that nestlings can reaffirm their social dominance status by monopolizing the nest box entrance. PMID:24828567

  4. Assessing accumulation and biliary excretion of naphthenic acids in yellow perch exposed to oil sands-affected waters.

    PubMed

    van den Heuvel, Michael R; Hogan, Natacha S; MacDonald, Gillian Z; Berrue, Fabrice; Young, Rozlyn F; Arens, Collin J; Kerr, Russell G; Fedorak, Phillip M

    2014-01-01

    Naphthenic acids are known to be the most prevalent group of organic compounds in oil sands tailings-associated waters. Yellow perch (Perca flavescens) were exposed for four months to oil sands-influenced waters in two experimental systems located on an oil sands lease 30 km north of Fort McMurray Alberta: the Demonstration Pond, containing oil sands tailings capped with natural surface water, and the South Bison Pond, integrating lean oil sands. Yellow perch were also sampled from three lakes: Mildred Lake that receives water from the Athabasca River, Sucker Lake, at the edge of oil sands extraction activity, and Kimowin Lake, a distant reference site. Naphthenic acids were measured in perch muscle tissue using gas chromatography-mass spectrometry (GC-MS). Bile metabolites were measured by GC-MS techniques and by high performance liquid chromatography (HPLC) with fluorescence detection at phenanthrene wavelengths. A method was developed using liquid chromatography-high resolution mass spectrometry (LC-HRMS) to evaluate naphthenic acids in bile. Tissue analysis did not show a pattern of naphthenic acids accumulation in muscle tissue consistent with known concentrations in exposed waters. Bile fluorescence and LC-HRMS methods were capable of statistically distinguishing samples originating from oil sands-influenced waters versus reference lakes. Although the GC-MS and HPLC fluorescence methods were correlated, there were no significant correlations of these methods and the LC-HRMS method. In yellow perch, naphthenic acids from oil sands sources do not concentrate in tissue at a measurable amount and are excreted through a biliary route. LC-HRMS was shown to be a highly sensitive, selective and promising technique as an indicator of exposure of biota to oil sands-derived naphthenic acids.

  5. Assessing accumulation and biliary excretion of naphthenic acids in yellow perch exposed to oil sands-affected waters.

    PubMed

    van den Heuvel, Michael R; Hogan, Natacha S; MacDonald, Gillian Z; Berrue, Fabrice; Young, Rozlyn F; Arens, Collin J; Kerr, Russell G; Fedorak, Phillip M

    2014-01-01

    Naphthenic acids are known to be the most prevalent group of organic compounds in oil sands tailings-associated waters. Yellow perch (Perca flavescens) were exposed for four months to oil sands-influenced waters in two experimental systems located on an oil sands lease 30 km north of Fort McMurray Alberta: the Demonstration Pond, containing oil sands tailings capped with natural surface water, and the South Bison Pond, integrating lean oil sands. Yellow perch were also sampled from three lakes: Mildred Lake that receives water from the Athabasca River, Sucker Lake, at the edge of oil sands extraction activity, and Kimowin Lake, a distant reference site. Naphthenic acids were measured in perch muscle tissue using gas chromatography-mass spectrometry (GC-MS). Bile metabolites were measured by GC-MS techniques and by high performance liquid chromatography (HPLC) with fluorescence detection at phenanthrene wavelengths. A method was developed using liquid chromatography-high resolution mass spectrometry (LC-HRMS) to evaluate naphthenic acids in bile. Tissue analysis did not show a pattern of naphthenic acids accumulation in muscle tissue consistent with known concentrations in exposed waters. Bile fluorescence and LC-HRMS methods were capable of statistically distinguishing samples originating from oil sands-influenced waters versus reference lakes. Although the GC-MS and HPLC fluorescence methods were correlated, there were no significant correlations of these methods and the LC-HRMS method. In yellow perch, naphthenic acids from oil sands sources do not concentrate in tissue at a measurable amount and are excreted through a biliary route. LC-HRMS was shown to be a highly sensitive, selective and promising technique as an indicator of exposure of biota to oil sands-derived naphthenic acids. PMID:24182406

  6. Distribution and exploitation of Nile perch Lates niloticus in relation to stratification in Lake Victoria, East Africa

    USGS Publications Warehouse

    Taabu-Munyaho, A.; Kayanda, Robert J.; Everson, Inigo; Grabowski, Timothy B.; Marteinsdóttir, Gudrún

    2013-01-01

    Stratification restricts habitable areas forcing fish to balance between favourable temperature and minimum dissolved oxygen requirements. Acoustic surveys conducted during the stratified and isothermal periods on tropical Lake Victoria indicated that stratification of temperature and dissolved oxygen (DO) affected vertical distribution of Nile perch. There was higher mean temperature (25.6 ± 0.5 °C) and lower DO (6.4 ± 1.8 mg/l) during stratified period compared to the isothermal period (mean temperature 24.9 ± 0.3 °C; mean DO 7.3 ± 0.6 mg/l). Higher mean densities of Nile perch were recorded in the coastal (0.44 ± 0.03) and deep (0.27 ± 0.02 g/m3) strata during the stratified compared to the isothermal season (coastal: 0.24 ± 0.01; deep: 0.12 ± 0.02 g/m3). In addition, Nile perch density in the upper 0–40 m depth layers in the coastal and deep strata increased by over 50% from the isothermal to the stratified season. Daily landings from 65 motorised fishing boats between October 2008 and September 2010 show higher mean catch (26.29 ± 0.17 kg/boat/day) during stratified compared to the isothermal (23.59 ± 0.15) season. Thermal stratification apparently compresses the habitat available to Nile perch and can potentially result in higher exploitation. Managers should evaluate the potential benefits of instituting closed seasons during the stratified period, and stock assessment models should take into account the seasonal niche compression.

  7. Perched groundwater-surface interactions and their consequences in stream flow generation in a semi-arid headwater catchment

    NASA Astrophysics Data System (ADS)

    Molenat, Jerome; Bouteffeha, Maroua; Raclot, Damien; Bouhlila, Rachida

    2013-04-01

    In semi-arid headwater catchment, it is usually admitted that stream flow comes predominantly from Hortonian overland flow (infiltration excess overland flow). Consequently, subsurface flow processes, and especially perched or shallow groundwater flow, have not been studied extensively. Here we made the assumption that perched groundwater flow could play a significant role in stream flow generation in semi-arid catchment. To test this assumption, we analyzed stream flow time series of a headwater catchment in the Tunisian Cap Bon region and quantified the flow fraction coming from groundwater discharge and that from overland flow. Furthermore, the dynamics of the perched groundwater was analyzed, by focusing on the different perched groundwater-surface interaction processes : diffuse and local infiltration, diffuse exfiltration, and direct groundwater discharge to the stream channel. This work is based on the 2.6 km² Kamech catchment (Tunisia), which belongs to the long term Mediterranean hydrological observatory OMERE (Voltz and Albergel, 2002). Results show that even though Hortonian overland flow was the main hydrological process governing the stream flow generation, groundwater discharge contribution to the stream channel annually accounted for from 10% to 20 % depending on the year. Furthermore, at some periods, rising of groundwater table to the soil surface in bottom land areas provided evidences of the occurrence of saturation excess overland flow processes during some storm events. Reference Voltz , M. and Albergel , J., 2002. OMERE : Observatoire Méditerranéen de l'Environnement Rural et de l'Eau - Impact des actions anthropiques sur les transferts de masse dans les hydrosystèmes méditerranéens ruraux. Proposition d'Observatoire de Recherche en Environnement, Ministère de la Recherche.

  8. Probing Microbial Activity in a Perched Water Body Located in a Deep Vadose Zone

    NASA Astrophysics Data System (ADS)

    Fujita, Y.; Taylor, J. L.; Henriksen, J. R.; Delwiche, M.; Gebrehiwet, T.; Hubbard, S. S.; Spycher, N.; Weathers, T. S.; Ginn, T. R.; Pfiffner, S. M.; Smith, R. W.

    2011-12-01

    Waste releases to the vadose zone are a legacy of past activities at a number of Department of Energy (DOE) facilities. At the Idaho National Laboratory (INL), 90Sr has been detected in perched water bodies underlying the Idaho Nuclear Technology and Engineering Center (INTEC) facility. Microbially induced calcite precipitation (MICP) using urea-hydrolyzing microbes is one proposed approach for immobilization of 90Sr in the subsurface. The sequestration mechanism is co-precipitation in calcite, promoted by the production of carbonate alkalinity from ureolysis. In order to assess the potential efficacy of MICP at INTEC a field study was conducted at the INL Vadose Zone Research Park (VZRP). The VZRP is located approximately 3 km from INTEC and shares many of the same hydrologic and lithologic features but in a non-contaminated setting. We conducted experiments over two field seasons in a perched water body located approximately 15 meters below land surface, using a 5-spot wellfield design. During the first season amendments (molasses and urea) were injected into the central well and water was extracted from two wells on either side, located along a diagonal. Water samples were characterized for microbial abundance, ureolytic activity and ureC gene numbers, along with solution composition. Before, during and after the injections cross-borehole geophysical imaging was performed, using various combinations of the available wells. During the second field season in situ static experiments were conducted to specifically characterize attached and unattached microbial communities, using surrogate substrates colonized during a 12 week incubation. Based on the field data a first order in situ urea hydrolysis rate constant of 0.034 d-1 was estimated. This was more than an order of magnitude higher than rate constants estimated above-ground using water samples, suggesting that attached microorganisms were responsible for >90% of the observed urea hydrolysis activity. The

  9. Waterscape genetics of the yellow perch (Perca flavescens): patterns across large connected ecosystems and isolated relict populations.

    PubMed

    Sepulveda-Villet, Osvaldo J; Stepien, Carol A

    2012-12-01

    Comparisons of a species' genetic diversity and divergence patterns across large connected populations vs. isolated relict areas provide important data for understanding potential response to global warming, habitat alterations and other perturbations. Aquatic taxa offer ideal case studies for interpreting these patterns, because their dispersal and gene flow often are constrained through narrow connectivity channels that have changed over geological time and/or from contemporary anthropogenic perturbations. Our research objective is to better understand the interplay between historic influences and modern-day factors (fishery exploitation, stocking supplementation and habitat loss) in shaping population genetic patterns of the yellow perch Perca flavescens (Percidae: Teleostei) across its native North American range. We employ a modified landscape genetics approach, analysing sequences from the entire mitochondrial DNA control region and 15 nuclear DNA microsatellite loci of 664 spawning adults from 24 populations. Results support that perch from primary glacial refugium areas (Missourian, Mississippian and Atlantic) founded contemporary northern populations. Genetic diversity today is highest in southern (never glaciated) populations and also is appreciable in northern areas that were founded from multiple refugia. Divergence is greater among isolated populations, both north and south; the southern Gulf Coast relict populations are the most divergent, reflecting their long history of isolation. Understanding the influence of past and current waterway connections on the genetic structure of yellow perch populations may help us to assess the roles of ongoing climate change and habitat disruptions towards conserving aquatic biodiversity.

  10. Timing, frequency and environmental conditions associated with mainstem-tributary movement by a lowland river fish, golden perch (Macquaria ambigua).

    PubMed

    Koster, Wayne M; Dawson, David R; O'Mahony, Damien J; Moloney, Paul D; Crook, David A

    2014-01-01

    Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007-2011). Fish were tagged and released in autumn 2007-2009 in the mid-Murray (n = 42) and lower Goulburn (n = 37) rivers within 3-6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem-tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem-tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers.

  11. Timing, Frequency and Environmental Conditions Associated with Mainstem–Tributary Movement by a Lowland River Fish, Golden Perch (Macquaria ambigua)

    PubMed Central

    Koster, Wayne M.; Dawson, David R.; O’Mahony, Damien J.; Moloney, Paul D.; Crook, David A.

    2014-01-01

    Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007–2011). Fish were tagged and released in autumn 2007–2009 in the mid-Murray (n = 42) and lower Goulburn (n = 37) rivers within 3–6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem–tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem–tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers. PMID:24788137

  12. Relationship between mercury accumulation in young-of-the-year yellow perch and water-level fluctuations

    USGS Publications Warehouse

    Sorensen, J.A.; Kallemeyn, L.W.; Sydor, M.

    2005-01-01

    A three-year (2001 -2003) monitoring effort of 14 northeastern Minnesota lakes was conducted to document relationships between water-level fluctuations and mercury bioaccumulation in young-of-the-year (YOY) yellow perch (Perca flavescens) collected in the fall of each year at fixed locations. Six of those lakes are located within or adjacent to Voyageurs National Park and are influenced by dams on the outlets of Rainy and Namakan lakes. One site on Sand Point Lake coincides with a location that has nine years of previous monitoring suitable for addressing the same issue over a longer time frame. Mean mercury concentrations in YOY yellow perch at each sampling location varied significantly from year to year. For the 12-year monitoring site on Sand Point Lake, values ranged from 38 ng gww-1 in 1998 to 200 ng gww -1 in 2001. For the 14-lake study, annual mean concentrations ranged by nearly a factor of 2, on average, for each lake over the three years of record. One likely factor responsible for these wide variations is that annual water-level fluctuations are strongly correlated with mercury levels in YOY perch for both data sets. ?? 2005 American Chemical Society.

  13. Timing, frequency and environmental conditions associated with mainstem-tributary movement by a lowland river fish, golden perch (Macquaria ambigua).

    PubMed

    Koster, Wayne M; Dawson, David R; O'Mahony, Damien J; Moloney, Paul D; Crook, David A

    2014-01-01

    Tributary and mainstem connections represent important links for the movement of fish and other biota throughout river networks. We investigated the timing, frequency and environmental conditions associated with movements by adult golden perch (Macquaria ambigua) between the mainstem of the mid-Murray River and a tributary, the Goulburn River, in south-eastern Australia, using acoustic telemetry over four years (2007-2011). Fish were tagged and released in autumn 2007-2009 in the mid-Murray (n = 42) and lower Goulburn (n = 37) rivers within 3-6 km of the mid-Murray-lower Goulburn junction. 38% of tagged fish undertook mainstem-tributary movements, characterised mostly by temporary occupation followed by return of fish to the original capture river. Approximately 10% of tagged fish exhibited longer-term shifts between the mainstem and tributary. Movement of fish from the tributary into the mainstem occurred primarily during the spawning season and in some years coincided with the presence of golden perch eggs/larvae in drift samples in the mainstem. Many of the tributary-to-mainstem movements occurred during or soon after changes in flow. The movements of fish from the mainstem into the tributary were irregular and did not appear to be associated with spawning. The findings show that golden perch moved freely across the mainstem-tributary interface. This demonstrates the need to consider the spatial, behavioural and demographic interdependencies of aquatic fauna across geographic management units such as rivers. PMID:24788137

  14. Exploitation of Erythrina dominguezii Hassl. (Fabaceae) nectar by perching birds in a dry forest in western Brazil.

    PubMed

    Ragusa-Netto, J

    2002-11-01

    Among the vertebrate pollinated plants, the genus Erythrina includes tree species in which birds are the pollen vectors. Two groups in this genus may be distinguished: a) the hummingbird, and b) the perching bird pollinated species. Erythrina dominguezii is included in the second group and occurs in deciduous/semi-deciduous forests in the southwestern neotropics. I studied the exploitation of Erythrina dominguezii nectar by perching birds in a dry forest in western Brazil. Six perching bird species from two distinct groups (Psittacidae: Brotogeris chiriri, Nandayus nenday, Aratinga acuticaudata; Icterinae: Psarocolius decumanus, Icterus cayanensis, I. icterus) consumed its nectar. The two most important consumers were Brotogeris chiriri (51.5% of the flowers visited by birds) and Psarocolius decumanus (20%). While B. chiriri was a flower predator, P. decumanus removed the nectar without damaging the flowers which it opened by inserting its large bill between the standard and the keel. Nandayus nenday, Aratinga acuticaudata, and I. icterus exploited the nectar like P. decumanus, and presumably also contributed to pollen transfer. As the flowering in E. dominguezii was intense and synchronous during the dryest period of the year, and its nectar was highly consumed by birds, the present data suggest that the nectar of this species may be important as an alternative resource to frugivorous/omnivorous birds when other resources are scarce.

  15. Effects of chlorpyrifos ethyl on acetylcholinesterase activity in climbing perch cultured in rice fields in the Mekong Delta, Vietnam.

    PubMed

    Nguyen, Tam Thanh; Berg, Håkan; Nguyen, Hang Thi Thuy; Nguyen, Cong Van

    2015-07-01

    Climbing perch is commonly harvested in rice fields and associated wetlands in the Mekong Delta. Despite its importance in providing food and income to local households, there is little information how this fish species is affected by the high use of pesticides in rice farming. Organophosphate insecticides, such as chlorpyrifos ethyl, which are highly toxic to aquatic organisms, are commonly used in the Mekong Delta. This study shows that the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings cultured in rice fields, was significantly inhibited by a single application of chlorpyrifos ethyl, at doses commonly applied by rice farmers (0.32-0.64 kg/ha). The water concentration of chlorpyrifos ethyl decreased below the detection level within 3 days, but the inhibition of brain AChE activity remained for more than 12 days. In addition, the chlorpyrifos ethyl treatments had a significant impact on the survival and growth rates of climbing perch fingerlings, which were proportional to the exposure levels. The results indicate that the high use of pesticides among rice farmers in the Mekong Delta could have a negative impact on aquatic organisms and fish yields, with implications for the aquatic biodiversity, local people's livelihoods and the aquaculture industry in the Mekong Delta. PMID:25828891

  16. Aerial perches and free-range laying hens: the effect of access to aerial perches and of individual bird parameters on keel bone injuries in commercial free-range laying hens.

    PubMed

    Donaldson, C J; Ball, M E E; O'Connell, N E

    2012-02-01

    The aim of this trial was to determine the effect of aerial perches on keel bone injuries and tibia bone characteristics in free-range laying hens. The relationship between keel bone injuries and individual bird parameters, such as weight, girth, wing:girth ratio, feather coverage, and tibia bone characteristics, was also assessed. Five commercial free-range houses, each containing between 7,000 and 8,000 birds, were used. The houses and range areas were divided in half; in half of the house, birds had access to aerial perches (P) and in the other half, they did not (NP). On 13 occasions between 17 and 70 wk of age, 20 birds per treatment were randomly selected from the slatted area and palpated for keel bone injury. At 72 wk of age, 30 birds per treatment in each of 4 houses were selected at random, weighed, and then euthanized. Girth and wing area and feather coverage were measured. The keel and left tibia bones were removed and keel bones were scored for injury. Tibia bones were weighed and diameter, length, breaking strength, and ash content recorded. Results indicated that access to aerial perches did not affect tibia bone measures (P > 0.05). Average palpated keel bone score increased with age of the hens (P < 0.001) but was not significantly affected by perch treatment (P > 0.05). There was a significant interaction between treatment and farm on keel bone injuries measured at dissection (P < 0.05), with the probability of birds having high keel-damage scores increasing in the perched treatment in some farms but not others. In general, as the keel bone injury score measured at dissection increased, the breaking strength (P < 0.001) and ash content (P < 0.05) of the tibia bone decreased. It is suggested that individual variation in bone strength contributes to differences in susceptibility to keel injury. No relationship existed between keel-injury score measured at dissection and individual parameters, such as weight, girth, or wing:girth ratio (P > 0

  17. The complete mitochondrial genome of jade perch, Scortum barcoo (Perciformes: Terapontidae: Scortum).

    PubMed

    Liu, Chun; Li, Kaibin; Wang, Qing; Wang, Fang; Zeng, Weiwei; Mai, Xiaomei; Wu, Shuqin

    2016-09-01

    This is the first documentation of the complete mitochondrial genome sequence of the jade perch, Scortum barcoo. The 16,843 bp mitogenome containes 37 genes (13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes) and two main non-coding regions (the control region and the origin of the light strand replication) as do other vertebrate mitogenomes. The overall base composition of S. barcoo is 27.39% for A, 24.74% for T, 31.14% for C and 16.73% for G, with a slight A + T bias of 52.13%. All protein-coding genes are initiated with ATG except for COX1, which begin with GTG instead. Meanwhile, the termination codons of 13 protein-coding genes are varied with TAA, TAG, TA, T or AGG. The measure of complete mitogenome sequence of S. barcoo will provide fundamental data for the phylogenetic and biogeographic studies of the Terapontidae.

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

    NASA Technical Reports Server (NTRS)

    2000-01-01

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

  19. An artificial perch to help Snail Kites handle an exotic Apple Snail

    USGS Publications Warehouse

    Pias, Kyle E.; Welch, Zach C.; Kitchens, Wiley M.

    2012-01-01

    In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.

  20. Genetic variability and glacial origins of yellow perch (Perca flavescens) in North America

    USGS Publications Warehouse

    Todd, Thomas N.; Hatcher, Charles O.

    1993-01-01

    Starch–gel electrophoresis was used to analyze muscle and liver tissue for variation in 13 enzymes representing 31 presumptive loci in yellow perch (Perca flavescens) from 13 localities scattered throughout the natural geographic range of the species in North America. Ten loci were polymorphic, but only three, alcohol dehydrogenase (ADH-1*), glucose-6-phosphate isomerase (GPI-1*), and phosphoglucomutase (PGM-2*), exhibited polymorphisms at relatively high frequencies across localities. Western populations were fixed for one allele at ADH-1*, eastern populations were fixed for another allele, and populations from intermediate locations in Lake Ontario and Pennsylvania had both alleles. The distributions of alleles at GPI-1* and PGM-2*were similar to that of ADH-1*, exhibiting strong differences between eastern and western populations, although the delineation was not as clear. Western populations were much less variable than eastern populations, and the distribution of alleles indicated that the two groups were derived from Mississippi and Atlantic glacial refugia. Populations near the physiographic discontinuity between the Mississippi and Atlantic drainages in western New York and Pennsylvania exhibited an admixture of typically western and eastern alleles. Such observations are consistent with the mixed faunal history of the region and limited postglacial dispersal of western and eastern populations across the boundary.

  1. Effects of freezing on white perch Morone americana (Gmelin, 1789): Implications for multivariate morphometrics

    USGS Publications Warehouse

    Kocovsky, Patrick

    2015-01-01

    This study tested the hypothesis that duration of freezing differentially affects whole-body morphometrics of a derived teleost. Whole-body morphometrics are frequently analyzed to test hypotheses of different species, or stocks within a species, of fishes. Specimens used for morphometric analyses are typically fixed or preserved prior to analysis, yet little research has been done on how fixation or preservation methods or duration of preservation of specimens might affect outcomes of multivariate statistical analyses of differences in shape. To determine whether whole-body morphometrics changed as a result of freezing, 23 whole-body morphometrics of age-1 white perch (Morone americana) from western Lake Erie (n = 211) were analyzed immediately after capture, after being held on ice overnight, and after freezing for 100 or 200 days. Discriminant function analysis revealed that all four groups differed significantly from one another (P < 0.0001). The first canonical axis reflected long-axis morphometrics, where there was a clear pattern of positive translation along this axis with duration of preservation. Re-classification analysis demonstrated fish were typically assigned to their original preservation class except for fish frozen 100 days, which assigned mostly to frozen 200 days. Morphometric comparisons using frozen fish must be done on fish frozen for identical periods of time to avoid biases related to the length of time they were frozen. Similar experiments should be conducted on other species and also using formalin- and alcohol-preserved specimens.

  2. Spotlight on fish: light pollution affects circadian rhythms of European perch but does not cause stress.

    PubMed

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Preuer, Torsten; Kloas, Werner

    2015-04-01

    Flora and fauna evolved under natural day and night cycles. However, natural light is now enhanced by artificial light at night, particularly in urban areas. This alteration of natural light environments during the night is hypothesised to alter biological rhythms in fish, by effecting night-time production of the hormone melatonin. Artificial light at night is also expected to increase the stress level of fish, resulting in higher cortisol production. In laboratory experiments, European perch (Perca fluviatilis) were exposed to four different light intensities during the night, 0 lx (control), 1 lx (potential light level in urban waters), 10 lx (typical street lighting at night) and 100 lx. Melatonin and cortisol concentrations were measured from water samples every 3h during a 24 hour period. This study revealed that the nocturnal increase in melatonin production was inhibited even at the lowest light level of 1 lx. However, cortisol levels did not differ between control and treatment illumination levels. We conclude that artificial light at night at very low intensities may disturb biological rhythms in fish since nocturnal light levels around 1 lx are already found in urban waters. However, enhanced stress induction could not be demonstrated.

  3. Stable isotope variability in tissues of the Eurasian perch Perca fluviatilis.

    PubMed

    Vollaire, Yan; Banas, Damien; Thomas, Marielle; Roche, Hélène

    2007-11-01

    Stable isotope analysis is frequently used as a complementary method of dietary analysis, to describe trophic relationships and assess food-web structure. These studies allow a precise determination, based on the calculation of a diet-tissue fractionation factor. The fractionation factor, determined for whole organisms or specific tissues, may vary substantially in natura. In the present study, delta13C and delta15N were assessed in lipid-free tissues (spleen, liver, viscera, scales, gills, spine, white muscle, brain) and in available energy reserves (proteins, glycogen, lipids) of Eurasian perch (Perca fluviatilis) reared under controlled conditions and fed for 4 months with the same artificial diet. Some discrepancies in delta15N and delta13C data were observed among tissues, respectively up to 3.43 per thousand and 2.54 per thousand for delta15N and delta13C. The 15N signature in organs depends on their metabolic activity. Despite a significant delta13C enrichment from feed to tissues, the lipids in spine, liver and viscera exhibit a certain stability.

  4. Design of nest access grids and perches in front of the nests: Influence on the behavior of laying hens.

    PubMed

    Stämpfli, K; Buchwalder, T; Fröhlich, E K F; Roth, B A

    2013-04-01

    In aviary systems for laying hens, it is important to provide suitable nest access platforms in front of the nests, allowing hens to reach and explore each of the nests easily. This access platform is needed to achieve good nest acceptance by the hens and thereby prevent mislaid eggs. In the present experiment, the behavior of hens using 2 different nest access platforms, a plastic grid and 2 wooden perches, was examined. Furthermore, the nests were placed on both sides of the aviary rack (corridor side and outdoor side), either integrated into the aviary rack itself (integrated nest; IN) or placed on the walls of the pens (wall nest; WN), resulting in a 2 × 2 factorial design Four thousand five hundred white laying hens were housed in 20 test pens. The eggs in the nests and mislaid eggs were collected daily, and the behavior of hens on the nest accesses was filmed during wk 25 and 26, using focal observation and scan sampling methods. More balancing, body contact, and agonistic interactions were expected for nests with perches, whereas more walking and nest inspections were expected for nests with grids. There were more mislaid eggs and balancing found in pens equipped with nests with wooden perches. More agonistic interactions and balancing, less standing, and a longer duration of nest inspection were found with the WN compared with the IN. Interactions between platform design and position of the nests were found for duration of nest visits, body contact, and walking, with the highest amount for WN equipped with plastic grids. Nests on the corridor side were favored by the hens. Nest-related behaviors, such as nest inspection, standing, and walking, decreased over time as did the number of hens on the nest accesses, whereas sitting increased. These results indicate that the hens had more difficulties in gripping the perches as designed. The lower number of hens on the nest access platforms in front of IN may be due to a better distribution around nests and tier

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

    PubMed

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

    2015-12-01

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

  6. Investigating bomb radiocarbon transport in the southern Pacific Ocean with otolith radiocarbon

    NASA Astrophysics Data System (ADS)

    Grammer, G. L.; Fallon, S. J.; Izzo, C.; Wood, R.; Gillanders, B. M.

    2015-08-01

    To explore the transport of carbon into water masses from the surface ocean to depths of ∼ 1000 m in the southwest Pacific Ocean, we generated time series of radiocarbon (Δ14C) from fish otoliths. Otoliths (carbonate earstones) from long-lived fish provide an indirect method to examine the "bomb pulse" of radiocarbon that originated in the 1950s and 1960s, allowing identification of changes to distributions of 14C that has entered and mixed within the ocean. We micro-sampled ocean perch (Helicolenus barathri) otoliths, collected at ∼ 400- 500 m in the Tasman Sea, to obtain measurements of Δ14C for those depths. We compared our ocean perch Δ14C series to published otolith-based marine surface water Δ14C values (Australasian snapper (Chrysophrys auratus) and nannygai (Centroberyx affinis)) and to published deep-water values (800-1000 m; orange roughy (Hoplostethus atlanticus)) from the southwest Pacific to establish a mid-water Δ14C series. The otolith bomb 14C results from these different depths were consistent with previous water mass results in the upper 1500 m of the southwest Pacific Ocean (e.g. World Ocean Circulation Experiment and Geochemical Ocean Sections Study). A comparison between the initial Δ14C bomb pulse rise at 400-500 m suggested a ventilation lag of 5 to 10 yr, whereas a comparison of the surface and depths of 800-1000 m detailed a 10 to 20 yr lag in the time history of radiocarbon invasion at this depth. Pre-bomb reservoir ages derived from otolith 14C located in Tasman Sea thermocline waters were ∼ 530 yr, while reservoir ages estimated for Tasman Antarctic intermediate water were ∼ 730 yr.

  7. CO2-induced ocean acidification increases anxiety in Rockfish via alteration of GABAA receptor functioning

    PubMed Central

    Hamilton, Trevor James; Holcombe, Adam; Tresguerres, Martin

    2014-01-01

    The average surface pH of the ocean is dropping at a rapid rate due to the dissolution of anthropogenic CO2, raising concerns for marine life. Additionally, some coastal areas periodically experience upwelling of CO2-enriched water with reduced pH. Previous research has demonstrated ocean acidification (OA)-induced changes in behavioural and sensory systems including olfaction, which is due to altered function of neural gamma-aminobutyric acid type A (GABAA) receptors. Here, we used a camera-based tracking software system to examine whether OA-dependent changes in GABAA receptors affect anxiety in juvenile Californian rockfish (Sebastes diploproa). Anxiety was estimated using behavioural tests that measure light/dark preference (scototaxis) and proximity to an object. After one week in OA conditions projected for the next century in the California shore (1125 ± 100 µatm, pH 7.75), anxiety was significantly increased relative to controls (483 ± 40 µatm CO2, pH 8.1). The GABAA-receptor agonist muscimol, but not the antagonist gabazine, caused a significant increase in anxiety consistent with altered Cl− flux in OA-exposed fish. OA-exposed fish remained more anxious even after 7 days back in control seawater; however, they resumed their normal behaviour by day 12. These results show that OA could severely alter rockfish behaviour; however, this effect is reversible. PMID:24285203

  8. Concentrations of 17 elements in the zebra mussel (Dreissena polymorpha), in different tissues of perch (Perca fluviatilis), and in perch intestinal parasites (Acanthocephalus lucii) from the subalpine lake Mondsee, Austria

    SciTech Connect

    Sures, B.; Steiner, W.; Rydlo, M.; Taraschewski, H.

    1999-11-01

    Concentrations of the elements Al, Ag, Ba, ca, Cd, Co, Cr, cu, Fe, Ga, Mg, Mn, Ni, Pb, Sr, Tl, and Zn were analyzed by inductively coupled plasma mass spectrometry in the acanthocephalan Acanthocephalus lucii (Mueller); in its host, Perca fluviatilis (L.), and in the soft tissue of the zebra mussel, Dreissena polymorpha (Pallas). All animals were collected from the same sampling site in a subalpine lake, Mondsee, in Austria. Most of the elements were found at significantly higher concentrations in the acanthocephalan than in different tissues (muscle, liver, and intestinal wall) of its perch host. Only Co was concentrated in the liver of perch to a level that was significantly higher than that found in the parasite. Most of the analyzed elements were also present at significantly higher concentrations in A. lucii than in D. polymorpha. Barium and Cr were the only elements recorded at higher concentrations in the mussel compared with the acanthocephalan. Thus, when comparing the accumulation of elements, the acanthocephalans appear to be even more suitable than the zebra mussels in terms of their use in the detection of metal contamination within aquatic biotopes. Spearman correlation analysis revealed that the concentrations of several elements within the parasites decreased with increasing infrapopulation. Furthermore, the levels of some elements in the perch liver were negatively correlated with the weight of A. lucii in the intestine. Thus, it emerged that not only is there competition for elements between acanthocephalans inside the gut but there is also competition for these elements between the host and the parasites. The elevated element concentrations demonstrated here in the parasitic worm A. lucii provide support for further investigations of these common helminthes and of their accumulation properties.

  9. Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The Arctic Ocean is the smallest of the Earth's four major oceans, covering 14x10(exp 6) sq km located entirely within the Arctic Circle (66 deg 33 min N). It is a major player in the climate of the north polar region and has a variable sea ice cover that tends to increase its sensitivity to climate change. Its temperature, salinity, and ice cover have all undergone changes in the past several decades, although it is uncertain whether these predominantly reflect long-term trends, oscillations within the system, or natural variability. Major changes include a warming and expansion of the Atlantic layer, at depths of 200-900 m, a warming of the upper ocean in the Beaufort Sea, a considerable thinning (perhaps as high as 40%) of the sea ice cover, a lesser and uneven retreat of the ice cover (averaging approximately 3% per decade), and a mixed pattern of salinity increases and decreases.

  10. Flow cytometric method for measuring chromatin fragmentation in fixed sperm from yellow perch (Perca flavescens)

    USGS Publications Warehouse

    Jenkins, Jill A.; Draugelis-Dale, Rassa O.; Pinkney, Alfred E.; Iwanowicz, Luke R.; Blazer, Vicki

    2015-01-01

    Declining harvests of yellow perch, Perca flavescens, in urbanized watersheds of Chesapeake Bay have prompted investigations of their reproductive fitness. The purpose of this study was to establish a flow cytometric technique for DNA analysis of fixed samples sent from the field to provide reliable gamete quality measurements. Similar to the sperm chromatin structure assay, measures were made on the susceptibility of nuclear DNA to acid-induced denaturation, but used fixed rather than live or thawed cells. Nuclei were best exposed to the acid treatment for 1 minute at 37 °C followed by the addition of cold (4 °C) propidium iodide staining solution before flow cytometry. The rationale for protocol development is presented graphically through cytograms. Field results collected in 2008 and 2009 revealed DNA fragmentation up to 14.5%. In 2008, DNA fragmentation from the more urbanized watersheds was significantly greater than from reference sites (P = 0.026) and in 2009, higher percentages of haploid testicular cells were noted from the less urbanized watersheds (P = 0.032) indicating better reproductive condition at sites with less urbanization. For both years, total and progressive live sperm motilities by computer-assisted sperm motion analysis ranged from 19.1% to 76.5%, being significantly higher at the less urbanized sites (P < 0.05). This flow cytometric method takes advantage of the propensity of fragmented DNA to be denatured under standard conditions, or 1 minute at 37 °C with 10% buffered formalin–fixed cells. The study of fixed sperm makes possible the restrospective investigation of germplasm fragmentation, spermatogenic ploidy patterns, and chromatin compaction levels from samples translocated over distance and time. The protocol provides an approach that can be modified for other species across taxa.

  11. Flow cytometric method for measuring chromatin fragmentation in fixed sperm from yellow perch (Perca flavescens).

    PubMed

    Jenkins, J A; Draugelis-Dale, R O; Pinkney, A E; Iwanowicz, L R; Blazer, V S

    2015-03-15

    Declining harvests of yellow perch, Perca flavescens, in urbanized watersheds of Chesapeake Bay have prompted investigations of their reproductive fitness. The purpose of this study was to establish a flow cytometric technique for DNA analysis of fixed samples sent from the field to provide reliable gamete quality measurements. Similar to the sperm chromatin structure assay, measures were made on the susceptibility of nuclear DNA to acid-induced denaturation, but used fixed rather than live or thawed cells. Nuclei were best exposed to the acid treatment for 1 minute at 37 °C followed by the addition of cold (4 °C) propidium iodide staining solution before flow cytometry. The rationale for protocol development is presented graphically through cytograms. Field results collected in 2008 and 2009 revealed DNA fragmentation up to 14.5%. In 2008, DNA fragmentation from the more urbanized watersheds was significantly greater than from reference sites (P = 0.026) and in 2009, higher percentages of haploid testicular cells were noted from the less urbanized watersheds (P = 0.032) indicating better reproductive condition at sites with less urbanization. For both years, total and progressive live sperm motilities by computer-assisted sperm motion analysis ranged from 19.1% to 76.5%, being significantly higher at the less urbanized sites (P < 0.05). This flow cytometric method takes advantage of the propensity of fragmented DNA to be denatured under standard conditions, or 1 minute at 37 °C with 10% buffered formalin-fixed cells. The study of fixed sperm makes possible the restrospective investigation of germplasm fragmentation, spermatogenic ploidy patterns, and chromatin compaction levels from samples translocated over distance and time. The protocol provides an approach that can be modified for other species across taxa. PMID:25559842

  12. Cyclic spattering, seismic tremor, and surface fluctuation within a perched lava channel, Kīlauea Volcano

    USGS Publications Warehouse

    Patrick, M.R.; Orr, T.; Wilson, D.; Dow, D.; Freeman, R.

    2011-01-01

    In late 2007, a perched lava channel, built up to 45 m above the preexisting surface, developed during the ongoing eruption near Pu‘u ‘Ō‘ō cone on Kīlauea Volcano’s east rift zone. The lava channel was segmented into four pools extending over a total of 1.4 km. From late October to mid-December, a cyclic behavior, consisting of steady lava level rise terminated by vigorous spattering and an abrupt drop in lava level, was commonly observed in pool 1. We use geologic observations, video, time-lapse camera images, and seismicity to characterize and understand this cyclic behavior. Spattering episodes occurred at intervals of 40–100 min during peak activity and involved small (5–10-m-high) fountains limited to the margins of the pool. Most spattering episodes had fountains which migrated downchannel. Each spattering episode was associated with a rapid lava level drop of about 1 m, which was concurrent with a conspicuous cigar-shaped tremor burst with peak frequencies of 4–5 Hz. We interpret this cyclic behavior to be gas pistoning, and this is the first documented instance of gas pistoning in lava well away from the deeper conduit. Our observations and data indicate that the gas pistoning was driven by gas accumulation beneath the visco-elastic component of the surface crust, contrary to other studies which attribute similar behavior to the periodic rise of gas slugs. The gas piston events typically had a gas mass of about 2,500 kg (similar to the explosions at Stromboli), with gas accumulation and release rates of about 1.1 and 5.7 kg s−1, respectively. The time-averaged gas output rate of the gas pistoning events accounted for about 1–2% of the total gas output rate of the east rift zone eruption.

  13. Adding Perches for Cross-Pollination Ensures the Reproduction of a Self-Incompatible Orchid

    PubMed Central

    Li, Li-Qiang; Rao, Wen-Hui; Zhang, Yu-Ting; Tang, Guang-Da; Huang, Lai-Qiang

    2013-01-01

    Background Outcrossing is known to carry genetic advantages in comparison with inbreeding. In many cases, flowering plants develop a self-incompatibility mechanism, along with a floral component adaptation mechanism, to avoid self-pollination and to promote outbreeding. Orchids commonly have a lip in their flower that functions as the a visiting plate for insect pollinators. Aside from the lip, however, many species (including Coelogyne rigida) have sheaths around the axis of inflorescence. The function of these sheaths remains unknown, and has long been a puzzle to researchers. Methodology/Principal Findings We investigated the function of these sheaths in relation to the lip and the pollinators, as well as their role in the modes of pollination and reproduction of Coelogyne rigida in 30 flowering populations of orchids in the limestone area of Southeast Yunnan, China. We found that self-incompatible C. rigida developed specialized bird perches around the basal axis of inflorescence to attract sunbirds and to complement their behavioral tendency to change foraging locations frequently. This self-incompatibility mechanism operates separately from the floral component adaptation mechanism. This mechanism thus prevents bees from repeatedly visiting the floral lip of the same plant which, in turn, results in autogamy. In this way, instead of preventing autogamy, C. rigida responds to these negative effects through a highly efficient cross-pollination method that successfully transfers pollen to different plants. Conclusions The proposed method ensures reproductive success, while offsetting the infertile self-pollination by insects, thereby reducing mating costs and addressing the lack of cross-pollination. The adaptation provides a novel and striking example of structural adaptation that promotes cross-pollination in angiosperms. PMID:23308277

  14. Effect of bioconcentration and trophic transfer on realized exposure to oxazepam in 2 predators, the dragonfly larvae (Aeshna grandis) and the Eurasian perch (Perca fluviatilis).

    PubMed

    Heynen, Martina; Fick, Jerker; Jonsson, Micael; Klaminder, Jonatan; Brodin, Tomas

    2016-04-01

    Psychoactive substances are used worldwide and constitute one of the most common groups of pharmaceutical contaminants in surface waters. Although these pharmaceuticals are designed to be efficiently eliminated from the human body, very little is known about their trophic-transfer potential in aquatic wildlife. Therefore, the goal of the present study was to quantify and compare uptake of an anxiolytic (oxazepam) from water (bioconcentration) and via the consumption of contaminated diet (trophic transfer) in 2 common freshwater predators: Eurasian perch (Perca fluviatilis) and the dragonfly larvae Aeshna grandis. Bioconcentration and trophic transfer of oxazepam were found in both predator species. However, higher bioconcentrations were observed for perch (bioconcentration factor [BCF], 3.7) than for dragonfly larvae (BCF, 0.5). Perch also retained more oxazepam from consumed prey (41%) than dragonfly larvae (10%), whereas the relative contribution via prey consumption was 14% and 42% for perch and dragonflies, respectively. In addition, bioconcentration was negatively correlated with perch weight, indicating that exposure levels in natural contaminated environments differ between individuals of different size or between different developmental stages. Hence, trophic transfer of pharmaceuticals may indeed occur, and estimates of environmental exposures that do not consider intake via food or size-dependent bioconcentration may therefore lead to wrongful estimations of realized exposure levels in natural contaminated ecosystems. PMID:26762222

  15. Integrated spatial health assessment of yellow perch (Perca flavescens) populations from the St. Lawrence River, Quebec, Canada) part A: physiological parameters and pathogen assessment.

    PubMed

    Giraudo, Maeva; Bruneau, Audrey; Gendron, Andrée D; Brodeur, Philippe; Pilote, Martin; Marcogliese, David J; Gagnon, Christian; Houde, Magali

    2016-09-01

    A multi-disciplinary approach was used to evaluate the health of yellow perch (Perca flavescens) in the St. Lawrence River (Quebec, Canada), which is experiencing a severe population decline in the downstream portion of the river. Physiological parameters, liver alterations, trace metal concentrations, parasite prevalence and abundance, stable isotope composition, and the presence/absence of the viral hemorragic septicemia virus (VHSV) were evaluated in perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island, and Lake St. Pierre (north and south). Trace metal concentrations in surface water were higher in Lake St. Louis and downstream of a major urban wastewater treatment plant discharge, indicating that this effluent was a significant source of Cu, As, Ag, Zn, and Cd. Levels of Pb in surface water exceeded thresholds for the protection of aquatic life in Lake St. Louis and were negatively correlated with body condition index in this lake. In Lake St. Pierre, Cu, Ag, and Cd bioaccumulated significantly in perch liver and lower body condition index and greater liver damage were observed compared to upstream sites. Parasite analyses indicated a higher abundance of metacercariae of the trematodes Apophallus brevis and Diplostomum spp. in Lake St. Louis, and VHSV was not detected in the liver of yellow perch for all studied sites. Overall, results suggested that the global health of yellow perch from Lake St. Pierre is lower compared to upstream studied sites, which could contribute to the documented population collapse at this site.

  16. Cloning and functional characterization of Δ6 fatty acid desaturase (FADS2) in Eurasian perch (Perca fluviatilis).

    PubMed

    Geay, F; Tinti, E; Mellery, J; Michaux, C; Larondelle, Y; Perpète, E; Kestemont, P

    2016-01-01

    The Eurasian perch (Perca fluviatilis) is a freshwater carnivorous species of high interest to diversify inland aquaculture. However, little is known about its ability to bioconvert polyunsaturated fatty acids (PUFAs) from plant oils into long chain polyunsaturated fatty acids (LC-PUFAs). In this study, special attention has been given to the fatty acid desaturase 2 (FADS2) which is commonly described to be a rate-limiting enzyme of the LC-PUFA biosynthesis. This work reports on the cloning, tissue expression and functional characterization of the Eurasian perch fads2, but also on the cloning of two alternative splicing transcripts named fads2-AS1 and fads2-AS2. The fads2 cDNA cloned is composed of an open reading frame (ORF) of 1338 nucleotides (nt) and encodes a protein of 445 amino acids. This deduced amino acid sequence displays the typical structure of microsomal FADS2 including two transmembrane domains and an N-terminal cytochrome b5 domain with the "HPGG" motif. Quantitative real-time PCR assay of fads2, fads2-AS1 and fads2-AS2 expressions revealed that the fads2 transcript was mainly expressed in the liver and intestine and exhibited a typical gene expression pattern of freshwater species while fads2-AS1 and fads2-AS2 genes were highly expressed in the brain, followed by the liver and intestine. Functional characterization of Eurasian perch FADS2 in transgenic yeast showed a fully functional Δ6 desaturation activity toward C18 PUFA substrates, without residual Δ5 and Δ8 desaturase activities.

  17. Bone-remodeling transcript levels are independent of perching in end-of-lay white leghorn chickens.

    PubMed

    Dale, Maurice D; Mortimer, Erin M; Kolli, Santharam; Achramowicz, Erik; Borchert, Glenn; Juliano, Steven A; Halkyard, Scott; Sietz, Nick; Gatto, Craig; Hester, Patricia Y; Rubin, David A

    2015-01-01

    Osteoporosis is a bone disease that commonly results in a 30% incidence of fracture in hens used to produce eggs for human consumption. One of the causes of osteoporosis is the lack of mechanical strain placed on weight-bearing bones. In conventionally-caged hens, there is inadequate space for chickens to exercise and induce mechanical strain on their bones. One approach is to encourage mechanical stress on bones by the addition of perches to conventional cages. Our study focuses on the molecular mechanism of bone remodeling in end-of-lay hens (71 weeks) with access to perches. We examined bone-specific transcripts that are actively involved during development and remodeling. Using real-time quantitative PCR, we examined seven transcripts (COL2A1 (collagen, type II, alpha 1), RANKL (receptor activator of nuclear factor kappa-B ligand), OPG (osteoprotegerin), PTHLH (PTH-like hormone), PTH1R (PTH/PTHLH type-1 receptor), PTH3R (PTH/PTHLH type-3 receptor), and SOX9 (Sry-related high mobility group box)) in phalange, tibia and femur. Our results indicate that the only significant effect was a difference among bones for COL2A1 (femur > phalange). Therefore, we conclude that access to a perch did not alter transcript expression. Furthermore, because hens have been used as a model for human bone metabolism and osteoporosis, the results indicate that bone remodeling due to mechanical loading in chickens may be a product of different pathways than those involved in the mammalian model. PMID:25625518

  18. Bone-Remodeling Transcript Levels Are Independent of Perching in End-of-Lay White Leghorn Chickens

    PubMed Central

    Dale, Maurice D.; Mortimer, Erin M.; Kolli, Santharam; Achramowicz, Erik; Borchert, Glenn; Juliano, Steven A.; Halkyard, Scott; Sietz, Nick; Gatto, Craig; Hester, Patricia Y.; Rubin, David A.

    2015-01-01

    Osteoporosis is a bone disease that commonly results in a 30% incidence of fracture in hens used to produce eggs for human consumption. One of the causes of osteoporosis is the lack of mechanical strain placed on weight-bearing bones. In conventionally-caged hens, there is inadequate space for chickens to exercise and induce mechanical strain on their bones. One approach is to encourage mechanical stress on bones by the addition of perches to conventional cages. Our study focuses on the molecular mechanism of bone remodeling in end-of-lay hens (71 weeks) with access to perches. We examined bone-specific transcripts that are actively involved during development and remodeling. Using real-time quantitative PCR, we examined seven transcripts (COL2A1 (collagen, type II, alpha 1), RANKL (receptor activator of nuclear factor kappa-B ligand), OPG (osteoprotegerin), PTHLH (PTH-like hormone), PTH1R (PTH/PTHLH type-1 receptor), PTH3R (PTH/PTHLH type-3 receptor), and SOX9 (Sry-related high mobility group box)) in phalange, tibia and femur. Our results indicate that the only significant effect was a difference among bones for COL2A1 (femur > phalange). Therefore, we conclude that access to a perch did not alter transcript expression. Furthermore, because hens have been used as a model for human bone metabolism and osteoporosis, the results indicate that bone remodeling due to mechanical loading in chickens may be a product of different pathways than those involved in the mammalian model. PMID:25625518

  19. Cloning and functional characterization of Δ6 fatty acid desaturase (FADS2) in Eurasian perch (Perca fluviatilis).

    PubMed

    Geay, F; Tinti, E; Mellery, J; Michaux, C; Larondelle, Y; Perpète, E; Kestemont, P

    2016-01-01

    The Eurasian perch (Perca fluviatilis) is a freshwater carnivorous species of high interest to diversify inland aquaculture. However, little is known about its ability to bioconvert polyunsaturated fatty acids (PUFAs) from plant oils into long chain polyunsaturated fatty acids (LC-PUFAs). In this study, special attention has been given to the fatty acid desaturase 2 (FADS2) which is commonly described to be a rate-limiting enzyme of the LC-PUFA biosynthesis. This work reports on the cloning, tissue expression and functional characterization of the Eurasian perch fads2, but also on the cloning of two alternative splicing transcripts named fads2-AS1 and fads2-AS2. The fads2 cDNA cloned is composed of an open reading frame (ORF) of 1338 nucleotides (nt) and encodes a protein of 445 amino acids. This deduced amino acid sequence displays the typical structure of microsomal FADS2 including two transmembrane domains and an N-terminal cytochrome b5 domain with the "HPGG" motif. Quantitative real-time PCR assay of fads2, fads2-AS1 and fads2-AS2 expressions revealed that the fads2 transcript was mainly expressed in the liver and intestine and exhibited a typical gene expression pattern of freshwater species while fads2-AS1 and fads2-AS2 genes were highly expressed in the brain, followed by the liver and intestine. Functional characterization of Eurasian perch FADS2 in transgenic yeast showed a fully functional Δ6 desaturation activity toward C18 PUFA substrates, without residual Δ5 and Δ8 desaturase activities. PMID:26478265

  20. The Ocean.

    ERIC Educational Resources Information Center

    Broecker, Wallace S.

    1983-01-01

    The chemistry of the ocean, whose constituents interact with those of air and land to support life and influence climate, is known to have undergone changes since the last glacial epoch. Changes in dissolved oxygen, calcium ions, phosphate, carbon dioxide, carbonate ions, and bicarbonate ions are discussed. (JN)

  1. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  2. SEM study of the effects of crude oil on the gills and air breathing organs of climbing perch, Anabas testudineus

    SciTech Connect

    Prasad, M.S. )

    1991-12-01

    Ultrastructural studies on the effects of crude oil on the gills are scanty. Recently, researchers studied the effect of crude oil on the air breathing organs of striped gourami using scanning electron microscope and observed mucous cell hyperplasia coupled with telangiectasis in the epithelia of air breathing organs. The present investigation has been undertaken to study crude oil toxicity by observing the morphological changes occurring in the epithelia of gills and air breathing organs of climbing perch, Anabas testudineus at SEM level. Since the epithelia of gills and air breathing organs function in two different media, a comparative account for their sensitivity to crude oil solutions would be informative.

  3. Nickel-induced histopathological alterations in the gill architecture of a tropical freshwater perch, Colisa fasciatus (Bloch & Schn.).

    PubMed

    Nath, K; Kumar, N

    1989-05-15

    The effect of a sub-lethal concentration of 64 ppm (2.279 x 10(-4) mol l-1) of nickel sulphate (NiSO4.7H2O) on the gill of a freshwater tropical perch, Colisa fasciatus, was investigated after 96 h exposure. Prominent changes noticed were: hypertrophy of respiratory and mucous cells; separation of the epithelial layer from the pillar cell system; cauterization and sloughing; extensive necrosis of the epithelium; and hyperplasia leading to clubbing at the tip of the lamellae.

  4. Characterisation of the genomes of four putative vesiculoviruses: tench rhabdovirus, grass carp rhabdovirus, perch rhabdovirus and eel rhabdovirus European X.

    PubMed

    Stone, David M; Kerr, Rose C; Hughes, Margaret; Radford, Alan D; Darby, Alistair C

    2013-11-01

    The complete coding sequences were determined for four putative vesiculoviruses isolated from fish. Sequence alignment and phylogenetic analysis based on the predicted amino acid sequences of the five main proteins assigned tench rhabdovirus and grass carp rhabdovirus together with spring viraemia of carp and pike fry rhabdovirus to a lineage that was distinct from the mammalian vesiculoviruses. Perch rhabdovirus, eel virus European X, lake trout rhabdovirus 903/87 and sea trout virus were placed in a second lineage that was also distinct from the recognised genera in the family Rhabdoviridae. Establishment of two new rhabdovirus genera, "Perhabdovirus" and "Sprivivirus", is discussed.

  5. Parasite communities of European perch, Perca fluviatilis L. (Actinopterygii: Perciformes: Percidae) from Lake Łebsko (Central Coast, Poland).

    PubMed

    Morozińska-Gogol, Jolanta

    2013-01-01

    Communities of parasites of European perch from lake Łebsko were studied and compared with similar communities from the Polish coastal zone. Parasites comprised 18 autogenic and 5 allogenic species. Most individual parasites belonged to allogenic species and were in larval stages. The majority of specimens were eye parasites with Tylodelphys clavata as the eudominant species. The dominant species, Acanthocephalus lucii, belongs to the intestine parasite community. Three marine species were found: Bothriocephalus scorpii, Hysterothylacium aduncum and Echinorchynhus gadi. The results indicate that the parasite fauna consists mostly of freshwater species, common in various types of European waters, while marine species were rarely observed. PMID:24171303

  6. Field-Derived Hydraulic Properties for Perched-Water Aquifer Wells 299-E33-350 and 299-E33-351, Hanford Site B-Complex Area

    SciTech Connect

    Newcomer, Darrell R.

    2014-07-01

    During February and March 2014, Pacific Northwest National Laboratory conducted hydraulic (slug) tests at 200-DV-1 Operable Unit wells 299-E33-350 (C8914) and 299-E33-351 (C8915) as part of B-Complex Area Perched-Water characterization activities at the Hanford Site 200-East Area. During the construction/completion phase of each well, two overlapping depth intervals were tested within the unconfined perched-water aquifer contained in the silty-sand subunit of the Cold Creek Unit. The purpose of the slug-test characterization was to provide estimates of transmissivity and hydraulic conductivity for the perched-water aquifer at these selected well locations.

  7. Remediating RDX-contaminated ground water with permanganate: laboratory investigations for the Pantex perched aquifer.

    PubMed

    Adam, M L; Comfort, S D; Morley, M C; Snow, D D

    2004-01-01

    Ground water beneath the U.S. Department of Energy Pantex Plant is contaminated with the high explosive RDX (hexahydro-1,3,5-trinitro-1,3,5 triazine). The USDOE Innovative Treatment and Remediation Demonstration (ITRD) program identified in situ oxidation by permanganate as a technology fit for further investigation. We evaluated the efficacy of KMnO(4) to transform and mineralize RDX by determining degradation kinetics and carbon mass balances using (14)C-RDX. Aqueous RDX solutions (2-5 mg L(-1)) and RDX-contaminated slurries (50% solids, w/v) were treated with KMnO(4) at 1000, 2000, 4000, and 20000 mg L(-1). Treating an aqueous RDX solution of 2.8 mg L(-1) with 20000 mg KMnO(4) L(-1) decreased RDX to 0.1 mg L(-1) within 11 d while cumulative mineralization proceeded for 14 d until 87% of the labeled carbon was trapped as (14)CO(2). Similar cumulative mineralization was obtained when Pantex aquifer material was included in the solution matrix. Other experiments using 4000 mg KMnO(4) L(-1) showed that initial RDX concentrations (1.3-10.4 mg L(-1)) or initial pH (4-11) had little effect on reaction rates. Attempts to identify RDX degradates and reaction products showed that N(2)O was a product of permanganate oxidation and constituted 20 to 30% of the N balance. Time-course measurements of a (14)C-RDX solution treated with KMnO(4) revealed few (14)C-labeled degradates but through liquid chromatography-mass spectrometry (LC-MS) analysis, we present evidence that 4-nitro-2,4-diaza-butanol is formed. Aquifer microcosm studies confirmed that the transformation products not mineralized by KMnO(4) were much more biodegradable than parent RDX. These results indicate permanganate can effectively transform and mineralize RDX in the presence of aquifer material and support its use as an in situ chemical oxidation treatment for the Pantex perched aquifer.

  8. Oceanic Lidar

    NASA Technical Reports Server (NTRS)

    Carder, K. L. (Editor)

    1981-01-01

    Instrument concepts which measure ocean temperature, chlorophyll, sediment and Gelbstoffe concentrations in three dimensions on a quantitative, quasi-synoptic basis were considered. Coastal zone color scanner chlorophyll imagery, laser stimulated Raman temperaure and fluorescence spectroscopy, existing airborne Lidar and laser fluorosensing instruments, and their accuracies in quantifying concentrations of chlorophyll, suspended sediments and Gelbstoffe are presented. Lidar applications to phytoplankton dynamics and photochemistry, Lidar radiative transfer and signal interpretation, and Lidar technology are discussed.

  9. A field and laboratory investigation of acid effects on largemouth bass, rock bass, black crappie, and yellow perch

    SciTech Connect

    Eaton, J.G.; McCormick, J.H. ); Swenson, W.A. ); Simonson, T.D. ); Jensen, K.M. )

    1992-09-01

    One-half of Little Rock Lake, a small seepage lake in north-central Wisconsin, was gradually acidified by additions of sulfuric acid between August 1983 and November 1990. The ambient pH (6.1) of the lake was reduced at successive 2-year intervals to pH 5.6, 5.1, and 4.7. Responses of largemouth bass Micropterus salmoides, rock bass Ambloplites rupestris, black crappie Pomoxis nigromaculatus, and yellow perch Perca flavescens populations to the pH reductions were recorded and compared to the responses of these species during in situ bioassays and laboratory toxicity tests on embryos and larvae. Laboratory results obtained for largemouth bass and rock bass underestimated, black crappie results overestimated, and yellow perch results were similar to effects observed in field studies. In situ bioassays predicted field responses better than did laboratory toxicity tests. Laboratory results showed that monomeric Al concentrations of approximately 50 [mu]g/L, which were comparable to Al concentrations in the acidified half of the lake, altered low-pH toxicity. Reduced recruitment was observed in field populations at higher pH than that at which adult mortality was observed. The results indicate that laboratory toxicity tests with early life stages may not accurately predict field population responses and that results from laboratory tests should be field-validated whenever possible. 42 refs., 2 figs., 7 tabs.

  10. Field and laboratory investigation of acid effects on largemouth bass, rock bass, black crappie, and yellow perch

    SciTech Connect

    Eaton, J.G.; Swenson, W.A.; McCormick, J.H.; Simonson, T.D.; Jensen, K.M.

    1992-01-01

    One-half of Little Rock Lake, a small seepage lake in north-central Wisconsin, was gradually acidified by additions of sulfuric acid between August 1983 and November 1990. The ambient pH (6.1) of the lake was reduced at successive 2-year intervals to pH 5.6, 5.1, and 4.7. Responses of largemouth bass Micropterus salmoides, rock bass Ambloplites rupestris, black crappie Pomoxis nigromaculatus, and yellow perch Perca flavescens populations to the pH reductions were recorded and compared to the responses of these species during in situ bioassays and laboratory toxicity tests on embryos and larvae. Laboratory results obtained for largemouth bass and rock bass underestimated, black crappie results overestimated, and yellow perch results were similar to effects observed in field studies. In situ bioassays predicted field responses better than did laboratory toxicity tests. Laboratory results showed that monomeric Al concentrations of approximately 50 microgram/l, which were comparable to Al concentrations in the acidified half of the lake, altered low-pH toxicity. Reduced recruitment was observed in field populations at higher pH than that at which adult mortality was observed. The results indicate that laboratory toxicity tests with early life stages may not accurately predict field population responses and that results from laboratory tests should be field-validated whenever possible.

  11. Perch-hunting in insectivorous Rhinolophus bats is related to the high energy costs of manoeuvring in flight.

    PubMed

    Voigt, Christian C; Schuller, B-Markus; Greif, Stefan; Siemers, Björn M

    2010-10-01

    Foraging behaviour of bats is supposedly largely influenced by the high costs of flapping flight. Yet our understanding of flight energetics focuses mostly on continuous horizontal forward flight at intermediate speeds. Many bats, however, perform manoeuvring flights at suboptimal speeds when foraging. For example, members of the genus Rhinolophus hunt insects during short sallying flights from a perch. Such flights include many descents and ascents below minimum power speed and are therefore considered energetically more expensive than flying at intermediate speed. To test this idea, we quantified the energy costs of short manoeuvring flights (<2 min) using the Na-bicarbonate technique in two Rhinolophus species that differ in body mass but have similar wing shapes. First, we hypothesized that, similar to birds, energy costs of short flights should be higher than predicted by an equation derived for bats at intermediate speeds. Second, we predicted that R. mehelyi encounters higher flight costs than R. euryale, because of its higher wing loading. Although wing loading of R. mehelyi was only 20% larger than that of R. euryale, its flight costs (2.61 ± 0.75 W; mean ± 1 SD) exceeded that of R. euryale (1.71 ± 0.37 W) by 50%. Measured flight costs were higher than predicted for R. mehelyi, but not for R. euryale. We conclude that R. mehelyi face elevated energy costs during short manoeuvring flights due to high wing loading and thus may optimize foraging efficiency by energy-conserving perch-hunting.

  12. Transcriptional response of yellow perch to changes in ambient metal concentrations-A reciprocal field transplantation experiment.

    PubMed

    Bougas, Bérénice; Normandeau, Eric; Grasset, Julie; Defo, Michel A; Campbell, Peter G C; Couture, Patrice; Bernatchez, Louis

    2016-04-01

    Recent local adaptation to pollution has been evidenced in several organisms inhabiting environments heavily contaminated by metals. Nevertheless, the molecular mechanisms underlying adaptation to high metal concentrations are poorly understood, especially in fishes. Yellow perch (Perca flavescens) populations from lakes in the mining area of Rouyn-Noranda (QC, Canada) have been faced with metal contamination for about 90 years. Here, we examine gene transcription patterns of fish reciprocally transplanted between a reference and a metal-contaminated lake and also fish caged in their native lake. After four weeks, 111 genes were differentially transcribed in metal-naïve fish transferred to the metal-contaminated lake, revealing a plastic response to metal exposure. Genes involved in the citric cycle and beta-oxidation pathways were under-transcribed, suggesting a potential strategy to mitigate the effects of metal stress by reducing energy turnover. However, metal-contaminated fish transplanted to the reference lake did not show any transcriptomic response, indicating a reduced plastic response capability to sudden reduction in metal concentrations. Moreover, the transcription of other genes, especially ones involved in energy metabolism, was affected by caging. Overall, our results highlight environmental stress response mechanisms in yellow perch at the transcriptomic level and support a rapid adaptive response to metal exposure through genetic assimilation. PMID:26867186

  13. Hepatic oxidative stress and metal subcellular partitioning are affected by selenium exposure in wild yellow perch (Perca flavescens).

    PubMed

    Ponton, Dominic E; Caron, Antoine; Hare, Landis; Campbell, Peter G C

    2016-07-01

    Yellow perch (Perca flavescens) collected from 11 lakes in the Canadian mining regions of Sudbury (Ontario) and Rouyn-Noranda (Quebec) display wide ranges in the concentrations of cadmium (Cd), nickel (Ni), selenium (Se), and thallium (Tl) in their livers. To determine if these trace elements, as well as copper (Cu) and zinc (Zn), are causing oxidative stress in these fish, we measured three biochemical indicators (glutathione (GSH), glutathione disulfide (GSSG) and thiobarbituric acid-reactive substances (TBARS)) in their livers. We observed that 44% of the yellow perch that we collected were at risk of cellular oxidative stress and lipid peroxidation. Considering all fish from all lakes, higher liver Se concentrations were coincident with both lower proportions of GSSG compared to GSH and lower concentrations of TBARS, suggesting that the essential trace-element Se acts as an antioxidant. Furthermore, fish suffering oxidative stress had higher proportions of Cd, Cu and Zn in potentially sensitive subcellular fractions (organelles and heat-denatured proteins) than did fish not suffering from stress. This result suggests that reactive oxygen species may oxidize metal-binding proteins and thereby reduce the capacity of fish to safely bind trace metals. High Cd concentrations in metal-sensitive subcellular fractions likely further exacerbate the negative effects of lower Se exposure. PMID:27131821

  14. Seasonal and year-to-year variation of mercury concentration in perch (Perca fluviatilis) in boreal lakes.

    PubMed

    Braaten, Hans Fredrik Veiteberg; Fjeld, Eirik; Rognerud, Sigurd; Lund, Espen; Larssen, Thorjørn

    2014-12-01

    The authors examined the seasonal and year-to-year variations of mercury (Hg) concentrations in populations of perch (Perca fluviatilis) from 2 boreal freshwater lakes in southeast Norway. Fish Hg concentrations were determined seasonally (spring, summer, and autumn) over 3 yr (2010, 2011, and 2012) to test the hypothesis that there are substantial changes in fish Hg concentrations during the year (seasonal variation) as well as annually. Concentrations were significantly (p < 0.0001) different in the 2 study lakes, with mean seasonal concentrations varying from 0.24 mg/kg to 0.36 mg/kg and from 0.29 mg/kg to 0.37 mg/kg, respectively. The Hg concentrations of both perch populations showed significant year-to-year (p < 0.0001) and seasonal variation (p < 0.01). The changing fish Hg concentrations were 25% and 28% (2010-2011) and 17% and 0% (2011-2012) in the 2 lakes over the 3 yr, respectively. The results demonstrate how the significant year-to-year increase is, among other variables, related to changes in trophic position, shown through stable nitrogen (δ(15)N) isotope data. The seasonal variation is related to summer growth dilution. The results highlight the clear need for yearly studies of fish Hg concentrations, rather than the 3-yr cycle suggested by current European policy through the Water Framework Directive. The lack of yearly sampling may result in erroneous conclusions regarding fish Hg concentration time trends.

  15. Molecular characterization of the myosatin gene and the effect of fasting on its expression in Chinese perch (Siniperca chuatsi).

    PubMed

    Liu, L; Li, Y L; Xu, S D; Wang, K Z; Wu, P; Chu, W Y; Wang, X Q

    2016-01-01

    Myostatin (MSTN) is an important member of the transforming growth factor-β (TGF-β) superfamily and is a muscle growth inhibitor. In the present study, we cloned the Chinese perch MSTN cDNA sequence and analyzed its expression patterns under various conditions. The MSTN full cDNA sequence was 3347 bp long, including an open-reading frame of 1131 bp, which encoded 376 amino acids. Sequence analysis demonstrated that the MSTN shared a highly conserved signal peptide, a TGF-β functional peptide, a hydrolytic site (RARR), and nine conservative cysteine residues with other members of the TGF-β superfamily. Sequence alignment and phylogenetic tree analyses indicated that the MSTN had a close relationship with teleostean fish, but they are far separated from mammals. Real-time polymerase chain reaction analysis revealed that the MSTN was strongly expressed in the skeletal muscle and heart tissues. Temporal expression analysis demonstrated that the MSTN gene was expressed in very low levels, from 20 to 90 dph (post-hatching development), and was at its highest level at 150 dph (P < 0.05). The fasting-re-feeding experiment showed that the expression of the MSTN gene was initially decreased in response to a single meal, after seven days of fasting, and subsequently increased significantly, and finally decreased back to its original level. Together, our results provided valuable knowledge regarding the regulation of MSTN gene expression in Chinese perch. PMID:27173303

  16. Transcriptional response of yellow perch to changes in ambient metal concentrations-A reciprocal field transplantation experiment.

    PubMed

    Bougas, Bérénice; Normandeau, Eric; Grasset, Julie; Defo, Michel A; Campbell, Peter G C; Couture, Patrice; Bernatchez, Louis

    2016-04-01

    Recent local adaptation to pollution has been evidenced in several organisms inhabiting environments heavily contaminated by metals. Nevertheless, the molecular mechanisms underlying adaptation to high metal concentrations are poorly understood, especially in fishes. Yellow perch (Perca flavescens) populations from lakes in the mining area of Rouyn-Noranda (QC, Canada) have been faced with metal contamination for about 90 years. Here, we examine gene transcription patterns of fish reciprocally transplanted between a reference and a metal-contaminated lake and also fish caged in their native lake. After four weeks, 111 genes were differentially transcribed in metal-naïve fish transferred to the metal-contaminated lake, revealing a plastic response to metal exposure. Genes involved in the citric cycle and beta-oxidation pathways were under-transcribed, suggesting a potential strategy to mitigate the effects of metal stress by reducing energy turnover. However, metal-contaminated fish transplanted to the reference lake did not show any transcriptomic response, indicating a reduced plastic response capability to sudden reduction in metal concentrations. Moreover, the transcription of other genes, especially ones involved in energy metabolism, was affected by caging. Overall, our results highlight environmental stress response mechanisms in yellow perch at the transcriptomic level and support a rapid adaptive response to metal exposure through genetic assimilation.

  17. Combined effects of temperature changes and metal contamination at different levels of biological organization in yellow perch.

    PubMed

    Grasset, Julie; Ollivier, Élodie; Bougas, Bérénice; Yannic, Glenn; Campbell, Peter G C; Bernatchez, Louis; Couture, Patrice

    2016-08-01

    In this study, we measured the effects of temperature (9°C, 20°C, and 28°C), metal contamination (cadmium and nickel) and their interaction on yellow perch (Perca flavescens) using liver enzymatic and transcriptomic endpoints and biometric indices. Kidney metal concentrations increased with a rise of temperature. The biometric indices analysed (Fulton condition factor, pyloric cæca, hepatosomatic and gonadosomatic indices) generally decreased with an increase of temperature but not with metal contamination. At the enzymatic level, the activity of superoxide dismutase (SOD), involved in antioxidant response, was affected by both temperature and metal contamination, whereas the activity of glucose-6-phosphate dehydrogenase (G6PDH), involved in energy accumulation but also in antioxidant response, was only affected by metal exposure. The response of perch to the stressors at the transcriptional level differed from the metabolic response. In particular, the transcription level of the cco and g6pdh genes sharply decreased with increasing temperature, while the activities of the corresponding enzymes remained stable. The normal response of the transcription level of the apoptotic gene (diablo) to heat stress was also altered in metal-contaminated fish. The combination of metal and temperature stresses also modified the response of antioxidant metabolism induced by these stressors individually. This study contributes to a better understanding of the influences of natural stressors like temperature on biomarkers commonly used in ecotoxicological studies and will facilitate their interpretation in the context of multiple stressors characteristic of field situations. PMID:27351718

  18. Effect of pH on Structural Changes in Perch Hemoglobin that Can Alter Redox Stability and Heme Affinity

    SciTech Connect

    Richards, Mark P.; Aranda, IV, Roman; He, Cai; Phillips, Jr., George N.

    2010-01-07

    pH can be manipulated to alter the oxidative stability of fish-based foods during storage. X-ray diffraction was used to investigate the ability of reduced pH to cause structural changes in fish hemoglobins that lead to enhanced oxidative degradation. Decreasing pH from 8.0 to 6.3 and 5.7 created a large channel for solvent entry into the heme crevice of perch hemoglobin beta chains. The proton-induced opening of this channel occurred between site CD3 and the heme-6-propionate. Solvent entry into the heme crevice can enhance metHb formation and hemin loss, processes that accelerate lipid oxidation. Reduced pH also decreased the distance between Ile at E11 in one of the alpha chains and the ligand above the heme iron atom. This sterically displaces O{sub 2} and protonated O{sub 2} which increases metHb formation. These studies demonstrate that pH reduction causes structural changes in perch hemoglobin which increase oxidative degradation of the heme pigment.

  19. Groundwater flow modeling of two-levels perched karstic leaking aquifers as a tool for estimating recharge and hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Peleg, Nadav; Gvirtzman, Haim

    2010-06-01

    SummaryPerched springs in nature emerge from aquifers laying on aquitards within the unsaturated zone, some of which emerge one above the other. A finite element model was introduced, using the FEFLOW code, for simulating the groundwater flow regime in each of these aquifers, for quantifying the fraction of rain that recharges the aquifers, and for estimating the hydrogeological parameters of the aquifers and aquitards. Many of the perched springs in Israel are found in the Judea Group aquifer, a stratified carbonate rock unit, characterised by a well-developed karst system. The Batir and Jamia springs exemplifies such a system, where Batir is the upper spring discharging at the contact between Aminadav and Moza Formations, and Jamia is the lower one, discharging at the contact between Kesalon and Sorek Formations. The 25-year-long measured spring's hydrographs were used to calibrate the spring's coefficients, the hydraulic conductivities of the different layers, the karst features and the yearly amount of rain recharging the spring.

  20. Characterization and expression analysis of laboratory of genetics and physiology 2 gene in sea perch, Lateolabrax japonicus.

    PubMed

    Jia, Peng; Zhang, Jing; Jin, Yilin; Zeng, Lin; Jia, Kuntong; Yi, Meisheng

    2015-11-01

    LGP2 (laboratory of genetics and physiology 2) as a key component of the retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), plays a predominant role in modulating RLRs-mediated cellular antiviral signaling during viral infection. In the present study, we cloned the LGP2 gene from the sea perch (Lateolabrax japonicus) (LjLGP2), an economically important farmed fish. The complete cDNA sequence of LjLGP2 was 2790 nt and encoded a polypeptide of 682 amino acids which contains four main structural domains: one DEAD/DEAH box helicase domain, one conserved restriction domain of bacterial type III restriction enzyme, one helicase superfamily c-terminal domain and one C-terminal domain of RIG-I, similar to most vertebrate LGP2. Subcellular localization analysis showed that LjLGP2 spanned the entire cytosol. The LjLGP2 mRNA was widespread expressed in the tested 10 tissues of healthy fish and significantly up-regulated post NNV infection. Furthermore, time course analysis showed that LjLGP2 transcripts significantly increased in the spleen, kidney and liver tissues after NNV infection. LjLGP2 mRNA expression was rapidly and significantly up-regulated in LJB cells after poly I:C stimulation and NNV infection. The present results suggest that LjLGP2 may be involved in recognization of NNV and play a role in antiviral innate immune against NNV in sea perch.

  1. Molecular cloning and expression analysis of a F-type lectin gene from Japanese sea perch (Lateolabrax japonicus).

    PubMed

    Qiu, Lihua; Lin, Liansheng; Yang, Keng; Zhang, Hanhua; Li, Jianzhu; Zou, Falin; Jiang, Shigui

    2011-08-01

    The techniques of homology cloning and anchored PCR were used to clone the fucose-binding lectin (F-type lectin) gene from Japanese sea perch (Lateolabrax Japonicus). The full-length cDNA of sea perch F-lectin (JspFL) contained a 5' untranslated region (UTR) of 39 bp, an ORF of 933 bp encoding a polypeptide of 310 amino acids with an estimated molecular mass of 10.82 kDa and a 3' UTR of 332 bp. The searches for nucleotides and protein sequence similarities with BLAST analysis indicated that the deduced amino acid sequence of JspFL was homological to the Fucose-binding lectin in other fish species. In the JspFL deduced amino acid sequence, two tandem domains that exhibit the eel carbohydrate-recognition sequence motif were found. The temporal expressions of gene in the different tissues were measured by real-time PCR. And the mRNA expressions of the gene were constitutively expressed in tissues including spleen, head-kidney, liver, gill, and heart. The JspFL expression in spleen was different during the stimulated time point, 2 h later the expression level became up-regulated, and 6 h later the expression level became down-regulated. The result indicated that JspFL was constitutive and inducible expressed and could play a critical role in the host-pathogen interaction.

  2. The Oceans

    NASA Astrophysics Data System (ADS)

    Karlsten, Jill

    For many practitioners of the marine sciences, including myself, one of the most alluring aspects of investigating the oceans is the need to marry the scientific disciplines. The complex linkages among geological, chemical, physical, and biological processes that govern the behavior and evolution of nearly 60% of the Earth's surface are fascinating and often surprising. Making progress in decoding this planetary fugue requires investigative strategies that fly squarely in the face of the increasing specialization that characterizes most modern scientific research. The successful oceanographer must endeavor to see the forest as well as the trees, or perhaps more fittingly, the kelp.

  3. Yellow perch larval survival studies and the potential effects of an ash storage facility in the Zekiah Swamp watershed, Wicomico River, Maryland

    SciTech Connect

    Buron, W.H.; Pinkney, A.E.; Gurley, J.

    1990-10-01

    Bioassay studies were conducted to determine if leachate from a coal ash depository was a potential factor in reducing abundance of yellow perch spawning stocks in Zekiah Swamp Run, a tributary of the Wicomico River, Maryland. In situ bioassays conducted in Zekiah Swamp Run in 1989 and 1990 using yellow perch yolk-sac larvae resulted in higher mortality upstream and downstream of the ash storage facility relative to reference stations in both years. Similar high mortality was observed at the upstream unaffected site and the downstream potentially affected site, suggesting that poor larval survival in these locations is a system-wide phenomenon. Analysis of water samples for metals, inorganic monomeric-aluminum, volatile organics, pH and measurements of physical parameters did not identify a specific cause for the high mortality observed. Surveys of the abundance and distribution of yellow perch egg strands during spring 1990 revealed that over 1,500 females spawned in a relatively restricted area in the vicinity of the fall line. In contrast to poor larval survival observed at upstream locations above the fall line, good survival was observed in bioassays conducted at a location below the fall line. Results to date are insufficient to establish the specific factors causing high mortality of larval yellow perch above the fall line. However, the ash storage site does not appear to be a contributing factor at the present time.

  4. Transcriptome Analysis and Postprandial Expression of Amino Acid Transporter Genes in the Fast Muscles and Gut of Chinese Perch (Siniperca chuatsi)

    PubMed Central

    Chen, Lin; Zeng, Ming; Wu, Yuanan; Wang, Jianhua; Zhang, Jianshe

    2016-01-01

    The characterization of the expression and regulation of growth-related genes in the muscles of Chinese perch is of great interest to aquaculturists because of the commercial value of the species. The transcriptome annotation of the skeletal muscles is a crucial step in muscle growth-related gene analysis. In this study, we generated 52 504 230 reads of mRNA sequence data from the fast muscles of the Chinese perch by using Solexa/Illumina RNA-seq. Twenty-one amino acid transporter genes were annotated by searching protein and gene ontology databases, and postprandial changes in their transcript abundance were assayed after administering a single satiating meal to Chinese perch juveniles (body mass, approximately 100 g), following fasting for 1 week. The gut content of the Chinese perch increased significantly after 1 h and remained high for 6 h following the meal and emptied within 48–96 h. Expression of eight amino acid transporter genes was assayed in the fast muscles through quantitative real-time polymerase chain reaction at 0, 1, 3, 6, 12, 24, 48, and 96 h. Among the genes, five transporter transcripts were markedly up-regulated within 1 h of refeeding, indicating that they may be potential candidate genes involved in the rapid-response signaling system regulating fish myotomal muscle growth. These genes display coordinated regulation favoring the resumption of myogenesis responding to feeding. PMID:27463683

  5. [HELMINTHS OF THE COMMON ROACH (RUTILUS RUTILUS LINNAEUS, 1758) AND THE EUROPEAN PERCH (PERCA FLUVIALITIS LINNAEUS, 1758) IN THE LAKE TERKHIIN TSAGAAN (MONGOLIA)].

    PubMed

    Lebedeva, D I; Mendsaikhan, B; Chantuu, Kh; Jargalmaa, G

    2015-01-01

    The article provides data about helminthes of the common roach and the European perch in the Lake Terkhiin Tsagaan (Mongolia). Six parasite species were found. Data on the occurrence of the trematode species and larvae of Streptocara crassicauda are obtained for the first time. Species composition of Diplostomum spp. metacercariae parasitizing in fish eyes is updated.

  6. Development of yellow perch (Perca flavescens) broodstocks: initial characterization of growth and quality traits following grow-out of different stocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broodstocks of yellow perch (Perca flavescens) were initiated from fertilized gametes obtained from wild fish taken from the Perquimans River (North Carolina), Choptank River (Maryland), Lake Winnebago (Wisconsin), and Lac du Flambeau (Wisconsin). Populations at these sites were chosen based on the ...

  7. From yellow perch to round goby: A review of double-crested cormorant diet and fish consumption at three St. Lawrence River colonies, 1999–2013

    USGS Publications Warehouse

    Johnson, James H.; Farquhar, James F; Klindt, Rodger M; Mazzocchi, Irene; Mathers, Alastair

    2015-01-01

    The number of double-crested cormorants (Phalacrocorax auritus) in the upper St. Lawrence River has increased markedly since the early 1990s. In 1999, a binational study was initiated to examine the annual diet composition and fish consumption of cormorants at colonies in the upper river. Since 1999, 14,032 cormorant pellets, collected from May through September each year, have been examined from St. Lawrence River colonies to estimate fish consumption and determine temporal and spatial variation in diet. Seasonal variation in diet composition within a colony was low. Prior to 2006 yellow perch was the primary fish consumed by cormorants in the upper St. Lawrence River. Round goby were first observed in cormorant diets in 2003 and by 2006 were the main fish consumed at two of the three colonies. The time interval it took from the first appearance of round goby in the diet at a colony to when goby were the dominant prey species varied by island, ranging from two to five years. Daily fish consumption at each cormorant colony increased significantly from the pre-round goby to post-round goby period. The mean annual biomass of yellow perch consumed decreased significantly during the post-round goby period at the three colonies. Reduced consumption of yellow perch by cormorants may alleviate suspected localized impacts on perch near some of the larger river colonies.

  8. A Transient Numerical Simulation of Perched Ground-Water Flow at the Test Reactor Area, Idaho National Engineering and Environmental Laboratory, Idaho, 1952-94

    SciTech Connect

    B. R. Orr

    1999-11-01

    Studies of flow through the unsaturated zone and perched ground-water zones above the Snake River Plain aquifer are part of the overall assessment of ground-water flow and determination of the fate and transport of contaminants in the subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL). These studies include definition of the hydrologic controls on the formation of perched ground-water zones and description of the transport and fate of wastewater constituents as they moved through the unsaturated zone. The definition of hydrologic controls requires stratigraphic correlation of basalt flows and sedimentary interbeds within the saturated zone, analysis of hydraulic properties of unsaturated-zone rocks, numerical modeling of the formation of perched ground-water zones, and batch and column experiments to determine rock-water geochemical processes. This report describes the development of a transient numerical simulation that was used to evaluate a conceptual model of flow through perched ground-water zones beneath wastewater infiltration ponds at the Test Reactor Area (TRA).

  9. Transcriptome Analysis and Postprandial Expression of Amino Acid Transporter Genes in the Fast Muscles and Gut of Chinese Perch (Siniperca chuatsi).

    PubMed

    Wu, Ping; Li, Yulong; Cheng, Jia; Chen, Lin; Zeng, Ming; Wu, Yuanan; Wang, Jianhua; Zhang, Jianshe; Chu, Wuying

    2016-01-01

    The characterization of the expression and regulation of growth-related genes in the muscles of Chinese perch is of great interest to aquaculturists because of the commercial value of the species. The transcriptome annotation of the skeletal muscles is a crucial step in muscle growth-related gene analysis. In this study, we generated 52 504 230 reads of mRNA sequence data from the fast muscles of the Chinese perch by using Solexa/Illumina RNA-seq. Twenty-one amino acid transporter genes were annotated by searching protein and gene ontology databases, and postprandial changes in their transcript abundance were assayed after administering a single satiating meal to Chinese perch juveniles (body mass, approximately 100 g), following fasting for 1 week. The gut content of the Chinese perch increased significantly after 1 h and remained high for 6 h following the meal and emptied within 48-96 h. Expression of eight amino acid transporter genes was assayed in the fast muscles through quantitative real-time polymerase chain reaction at 0, 1, 3, 6, 12, 24, 48, and 96 h. Among the genes, five transporter transcripts were markedly up-regulated within 1 h of refeeding, indicating that they may be potential candidate genes involved in the rapid-response signaling system regulating fish myotomal muscle growth. These genes display coordinated regulation favoring the resumption of myogenesis responding to feeding. PMID:27463683

  10. Species richness and diversity of the parasites of two predatory fish species - perch (Perca fluviatilis Linnaeus, 1758) and zander (Sander lucioperca Linnaeus, 1758) from the Pomeranian Bay.

    PubMed

    Bielat, Iwona; Legierko, Monika; Sobecka, Ewa

    2015-01-01

    Pomeranian Bay as an ecotone is a transition zone between two different biocenoses, which is characterized by an increase in biodiversity and species density. Therefore, Pomeranian Bay is a destination of finding and reproductive migrations of fish from the rivers entered the area. The aim of the study was to compare parasitic fauna of two predatory fish species from the Pomeranian Bay, collected from the same fishing grounds at the same period. A total of 126 fish studied (53 perches and 73 zanders) were collected in the summer 2013. Parasitological examinations included: skin, fins, gills, vitreous humour and lens of the eye, mouth cavity, body cavity and internal organs. Apart from the prevalence and intensity of infection (mean, range) the parasite communities of both fish species were compared. European perch and zander were infected with parasites from five different taxonomic units. The most numerous parasites were Diplostomum spp. in European perch and Bucephalus polymorphus in zander. The prevalence of infection of European perch ranged from 5.7% (Diphyllobothrium latum) to 22.3% (Diplostomum spp.) and for zander from 1.4% (Ancyrocephalus paradoxus, Hysterothylacium aduncum) to 12.3% (Bucephalus polymorphus). Different composition of the parasitic fauna is likely due to the different biology of both fish species. PMID:26342503

  11. Integrated spatial health assessment of yellow perch (Perca flavescens) populations from the St. Lawrence River (QC, Canada), part B: cellular and transcriptomic effects.

    PubMed

    Bruneau, Audrey; Landry, Catherine; Giraudo, Maeva; Douville, Mélanie; Brodeur, Philippe; Boily, Monique; Gagnon, Pierre; Houde, Magali

    2016-09-01

    Multi-biological level assessments have become great tools to evaluate the health of aquatic ecosystems. Using this approach, a complementary study was designed to evaluate the health of yellow perch (Perca flavescens) populations in the St. Lawrence River (Quebec, Canada). In the present study, stress responses were compared at the transcriptomic, cellular, and tissue levels in yellow perch collected at six sites along the river: Lake St. François, Lake St. Louis (north and south), Beauregard Island and Lake St. Pierre (north and south). These results complement the physiological and chemical parameters as well as pathogen infection investigated in a companion paper published in the present issue. Thiobarbituric acid reactive substance (TBARS) analyses indicated the presence of oxidative stress in fish collected in the southern part of Lake St. Louis and at the downstream sites of Lake St. Pierre. High lipid peroxidation levels were found in the muscle of yellow perch caught at Beauregard Island, located downstream of the Montreal's wastewater treatment plant, suggesting an impact of the municipal effluent on redox homeostasis. Transcriptomic results indicated the down-regulation of genes related to lipid, glucose, and retinoid in southern Lake St. Pierre as well as a decrease in retinoid storage. Overall, biochemical and molecular markers indicated that the health status of yellow perch followed a decreasing gradient from upstream to downstream of the St. Lawrence River. This gradient is representative of the cumulative negative impacts of human activities on water and habitat quality along the river. PMID:27272701

  12. Display of ISKNV orf086 protein on the surface of Aeromonas hydrophila and its immunogenicity in Chinese perch (Siniperca chuatsi).

    PubMed

    Fu, Xiaozhe; Lin, Qiang; Liu, Lihui; Liang, Hongru; Huang, Zhibin; Li, Ningqiu

    2016-09-01

    Co-infection with infectious spleen and kidney necrosis virus (ISKNV) and Aeromonas hydrophila is becoming ever more widespread in Chinese perch (Siniperca chuatsi) aquaculture industry, so that it's necessary to develop the combined vaccine against ISKNV and A. hydrophila disease. The surface display of heterologous on bacteria using anchoring motifs from outer membranes proteins has already been explored as an effective delivery system of viral antigens. In present study, the ISKNV orf086 gene, which is verified as a protective antigen, was inserted into ompA gene cassette of A. hydrophila GYK1 strain by homologous recombination. And an ompA-orf086 fusion A. hydrophila mutant strain K28 was constructed. Then the ISKNV orf086 was verified to express on the surface of A. hydrophila K28 by RT-PCR, western blot and indirect immunofluorescence assay. Next, Chinese perch were intraperitoneally inoculated with formalin inactivated A. hydrophila k28 emulsified with ISA763 adjuvant with a dose of 9 × 10(8) CFU per fish. Transcriptional analysis of non-specific and specific immune related genes revealed that the expression levels of IRF-7, IRAK1, Mx, Viperin, Lysozyme and IgM were strongly up-regulated in Chinese perch post-inoculation. In addition, specific antibodies were detected by ELISA, and the results showed that antibody titer against ISKNV or A. hydrophila reached the highest with 1:800 or 1:1200 on 14dpv, respectively. Lymphocyte proliferation were detected by MTT methods, and the results showed that the SI values of AH-K28 vaccinated group to three different stimulators were significantly higher than those of control group. At last, protective efficacy were determined by challenge trials. The cumulative mortality rates of vaccinated groups were significantly lower than the control one (P < 0.05) after ISKNV or A. hydrophila challenge, and the relative percentage survival (RPS) value was 73.3% and 60%, respectively. This system provides a novel approach to

  13. Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. II: live weight, health measures and perching.

    PubMed

    Steenfeldt, S; Nielsen, B L

    2015-09-01

    Multi-tier aviary systems, where conveyor belts below the tiers remove the manure at regular intervals, are becoming more common in organic egg production. The area on the tiers can be included in the net area available to the hens (also referred to as usable area) when calculating maximum indoor stocking densities in organic systems within the EU. In this article, results on live weight, health measures and perching are reported for organic laying hens housed in a multi-tier system with permanent access to a veranda and kept at stocking densities (D) of 6, 9 and 12 hens/m2 available floor area, with concomitant increases in the number of hens per trough, drinker, perch and nest space. In a fourth treatment, access to the top tier was blocked reducing vertical, trough, and perch access at the lowest stocking density (D6x). In all other aspects than stocking density, the experiment followed the EU regulations on the keeping of organic laying hens. Hen live weight, mortality and foot health were not affected by the stocking densities used in the present study. Other variables (plumage condition, presence of breast redness and blisters, pecked tail feathers, and perch use) were indirectly affected by the increase in stocking density through the simultaneous reduction in access to other resources, mainly perches and troughs. The welfare of the hens was mostly affected by these associated constraints, despite all of them being within the allowed minimum requirements for organic production in the EU. Although the welfare consequences reported here were assessed to be moderate to minor, it is important to take into account concurrent constraints on access to other resources when higher stocking densities are used in organic production.

  14. Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. II: live weight, health measures and perching.

    PubMed

    Steenfeldt, S; Nielsen, B L

    2015-09-01

    Multi-tier aviary systems, where conveyor belts below the tiers remove the manure at regular intervals, are becoming more common in organic egg production. The area on the tiers can be included in the net area available to the hens (also referred to as usable area) when calculating maximum indoor stocking densities in organic systems within the EU. In this article, results on live weight, health measures and perching are reported for organic laying hens housed in a multi-tier system with permanent access to a veranda and kept at stocking densities (D) of 6, 9 and 12 hens/m2 available floor area, with concomitant increases in the number of hens per trough, drinker, perch and nest space. In a fourth treatment, access to the top tier was blocked reducing vertical, trough, and perch access at the lowest stocking density (D6x). In all other aspects than stocking density, the experiment followed the EU regulations on the keeping of organic laying hens. Hen live weight, mortality and foot health were not affected by the stocking densities used in the present study. Other variables (plumage condition, presence of breast redness and blisters, pecked tail feathers, and perch use) were indirectly affected by the increase in stocking density through the simultaneous reduction in access to other resources, mainly perches and troughs. The welfare of the hens was mostly affected by these associated constraints, despite all of them being within the allowed minimum requirements for organic production in the EU. Although the welfare consequences reported here were assessed to be moderate to minor, it is important to take into account concurrent constraints on access to other resources when higher stocking densities are used in organic production. PMID:25990629

  15. Gonadal histopathology following nickel intoxication in the giant gaurami Colisa fasciatus (Bloch and Schneider), a freshwater tropical perch

    SciTech Connect

    Nath, K.; Kumar, N. )

    1990-08-01

    Large variety of data regarding toxic effects of nickel on mammals has been reported. Nickel refinery workers had increased mortality from lung or sinonasal cancers. In human populations exposed to nickel and chromium compounds, chromosomal abberations have been reported. Biochemical as well as histopathological alterations arising from nickel exposure in mammals have also been documented. Very scanty data is available concerning histopathological impact of nickel on fish tissues. However, to the authors' knowledge, there are no reports available on the fish gonads of either sex encountered with nickel. The present study appears to be the first report on the topic. Therefore, in the present investigation impact of nickel on the histological architecture of gonads of both sexes of a freshwater tropical perch, Colisa fasciatus have been assessed.

  16. Effects of turbidity and prey density on the foraging success of age 0 year yellow perch Perca flavescens.

    PubMed

    Wellington, C G; Mayer, C M; Bossenbroek, J M; Stroh, N A

    2010-05-01

    Laboratory experiments were conducted to determine how larval and juvenile yellow perch Perca flavescens respond to changes in prey density when exposed to different levels and types of turbidity (phytoplanktonic or sedimentary). Across prey densities, consumption by P. flavescens tended to be less in phytoplanktonic turbidity compared with sedimentary turbidity. For larvae, this effect was dependent on turbidity level (consumption differed between turbidity types only at high turbidity), while for juveniles the difference with turbidity type was equal across turbidity levels. These results suggest that phytoplankton blooms are detrimental to the ability of late season age 0 year P. flavescens to forage and support the need to control factors leading to excessive phytoplankton growth in lakes.

  17. Perch-height specific predation on tropical lizard clay models: implications for habitat selection in mainland neotropical lizards.

    PubMed

    Steffen, John E

    2009-09-01

    Predation has been hypothesized to be a strong selective force structuring communities of tropical lizards. Comparisons of perch height and size-based predation frequencies can provide a unique window into understanding how predation might shape habitat selection and morphological patterns in lizards, especially anoles. Here I use plasticine clay models, placed on the trunks of trees and suspended in the canopy to show that predation frequency on clay models differs primarily according to habitat (canopy vs. trunk-ground), but not according to size. These data are discussed in light of observed lizard abundances in the lowland forests of Costa Rica, and are presented as partial explanation for why fewer lizards are found in tree canopies, and more lizards are found on ground-trunk habitats.

  18. Susceptibility of Chinese Perch Brain (CPB) Cell and Mandarin Fish to Red-Spotted Grouper Nervous Necrosis Virus (RGNNV) Infection

    PubMed Central

    Tu, Jiagang; Chen, Wenjie; Fu, Xiaozhe; Lin, Qiang; Chang, Ouqin; Zhao, Lijuan; Lan, Jiangfeng; Li, Ningqiu; Lin, Li

    2016-01-01

    Nervous necrosis virus (NNV) is the causative agent of viral encephalopathy and retinopathy (VER), a neurological disease responsible for high mortality of fish species worldwide. Taking advantage of our established Chinese perch brain (CPB) cell line derived from brain tissues of Mandarin fish (Siniperca chuatsi), the susceptibility of CPB cell to Red-Spotted Grouper nervous necrosis virus (RGNNV) was evaluated. The results showed that RGNNV replicated well in CPB cells, resulting in cellular apoptosis. Moreover, the susceptibility of Mandarin fish to RGNNV was also evaluated. Abnormal swimming was observed in RGNNV-infected Mandarin fish. In addition, the cellular vacuolation and viral particles were also observed in brain tissues of RGNNV-infected Mandarin fish by Hematoxylin-eosin staining or electronic microscopy. The established RGNNV susceptible brain cell line from freshwater fish will pave a new way for the study of the pathogenicity and replication of NNV in the future. PMID:27213348

  19. Methylation status and chromatin structure of the myostatin gene promoter region in the sea perch Lateolabrax japonicus (Perciformes).

    PubMed

    Abbas, E M; Takayanagi, A; Shimizu, N; Kato, M

    2011-01-01

    Myostatin is a negative regulator of the growth and development of skeletal muscle mass. In fish, myostatin is expressed in several organs in addition to skeletal muscle. To understand the mechanisms regulating myostatin gene expression in the sea perch, Lateolabrax japonicus, we examined the methylation status of the myostatin gene promoter region in several tissues (liver, eye, kidney, brain, and heart) isolated from adult specimens. The frequency of methylated cytosines was very low in all tissues, regardless of the level of myostatin expression, suggesting that DNA methylation is not involved in the tissue-specific regulation of myostatin expression. Southern blot analysis of genomic DNA obtained from micrococcal nuclease-treated nuclei showed that chromatin digestion occurs in tissues where the myostatin gene is actively transcribed and that the myostatin gene is protected from micrococcal nuclease in tissues where myostatin is not expressed. The chromatin structure in the myostatin gene region appears to regulate its expression without DNA methylation. PMID:22183947

  20. Perch-height specific predation on tropical lizard clay models: implications for habitat selection in mainland neotropical lizards.

    PubMed

    Steffen, John E

    2009-09-01

    Predation has been hypothesized to be a strong selective force structuring communities of tropical lizards. Comparisons of perch height and size-based predation frequencies can provide a unique window into understanding how predation might shape habitat selection and morphological patterns in lizards, especially anoles. Here I use plasticine clay models, placed on the trunks of trees and suspended in the canopy to show that predation frequency on clay models differs primarily according to habitat (canopy vs. trunk-ground), but not according to size. These data are discussed in light of observed lizard abundances in the lowland forests of Costa Rica, and are presented as partial explanation for why fewer lizards are found in tree canopies, and more lizards are found on ground-trunk habitats. PMID:19928477

  1. Susceptibility of Chinese Perch Brain (CPB) Cell and Mandarin Fish to Red-Spotted Grouper Nervous Necrosis Virus (RGNNV) Infection.

    PubMed

    Tu, Jiagang; Chen, Wenjie; Fu, Xiaozhe; Lin, Qiang; Chang, Ouqin; Zhao, Lijuan; Lan, Jiangfeng; Li, Ningqiu; Lin, Li

    2016-01-01

    Nervous necrosis virus (NNV) is the causative agent of viral encephalopathy and retinopathy (VER), a neurological disease responsible for high mortality of fish species worldwide. Taking advantage of our established Chinese perch brain (CPB) cell line derived from brain tissues of Mandarin fish (Siniperca chuatsi), the susceptibility of CPB cell to Red-Spotted Grouper nervous necrosis virus (RGNNV) was evaluated. The results showed that RGNNV replicated well in CPB cells, resulting in cellular apoptosis. Moreover, the susceptibility of Mandarin fish to RGNNV was also evaluated. Abnormal swimming was observed in RGNNV-infected Mandarin fish. In addition, the cellular vacuolation and viral particles were also observed in brain tissues of RGNNV-infected Mandarin fish by Hematoxylin-eosin staining or electronic microscopy. The established RGNNV susceptible brain cell line from freshwater fish will pave a new way for the study of the pathogenicity and replication of NNV in the future. PMID:27213348

  2. Planet Ocean

    NASA Astrophysics Data System (ADS)

    Afonso, Isabel

    2014-05-01

    A more adequate name for Planet Earth could be Planet Ocean, seeing that ocean water covers more than seventy percent of the planet's surface and plays a fundamental role in the survival of almost all living species. Actually, oceans are aqueous solutions of extraordinary importance due to its direct implications in the current living conditions of our planet and its potential role on the continuity of life as well, as long as we know how to respect the limits of its immense but finite capacities. We may therefore state that natural aqueous solutions are excellent contexts for the approach and further understanding of many important chemical concepts, whether they be of chemical equilibrium, acid-base reactions, solubility and oxidation-reduction reactions. The topic of the 2014 edition of GIFT ('Our Changing Planet') will explore some of the recent complex changes of our environment, subjects that have been lately included in Chemistry teaching programs. This is particularly relevant on high school programs, with themes such as 'Earth Atmosphere: radiation, matter and structure', 'From Atmosphere to the Ocean: solutions on Earth and to Earth', 'Spring Waters and Public Water Supply: Water acidity and alkalinity'. These are the subjects that I want to develop on my school project with my pupils. Geographically, our school is located near the sea in a region where a stream flows into the sea. Besides that, our school water comes from a borehole which shows that the quality of the water we use is of significant importance. This project will establish and implement several procedures that, supported by physical and chemical analysis, will monitor the quality of water - not only the water used in our school, but also the surrounding waters (stream and beach water). The samples will be collected in the borehole of the school, in the stream near the school and in the beach of Carcavelos. Several physical-chemical characteristics related to the quality of the water will

  3. The microRNA signature in response to nutrient restriction and refeeding in skeletal muscle of Chinese perch (Siniperca chuatsi).

    PubMed

    Zhu, Xin; Chen, Dunxue; Hu, Yi; Wu, Ping; Wang, Kaizuo; Zhang, Junzhi; Chu, Wuying; Zhang, Jianshe

    2015-04-01

    The Chinese perch (Siniperca chuatsi) is one of the most commercially important carnivorous fish species in aquaculture with its large-scale culture in China. Increasing evidence suggests that microRNAs (miRNAs) play an important role in muscle cell proliferation and differentiation. However, the knowledge of the identity of myogenic miRNAs and the effect of nutrient status on miRNA expression in teleost remains limited. In the present study, among the 21 miRNAs identified with high abundance in the fast muscle of adult Chinese perch, 19 miRNAs were differentially expressed in the adults and juveniles. The postprandial changes in the transcript abundance were determined for the 21 miRNAs following a single satiating meal in the juveniles after fasting for 1 week. The results showed that the seven miRNAs (miR-10c, miR-107a, miR-133a-3p, miR-140-3p, miR-181a-5p, miR-206, and miR-214) were sharply upregulated or downregulated within 1 h after refeeding. These miRNAs may be the promising candidate miRNAs involved in a fast-response signaling system that regulates fish skeletal muscle growth. Target prediction and expressional analysis suggested that four miRNAs (miR-10c, miR-107a, miR-140-3p, and miR-181a-5p) might play a role in regulating the translation of target gene transcripts such as myostatin following acute anabolic stimuli.

  4. Cardiac oxygen limitation during an acute thermal challenge in the European perch: effects of chronic environmental warming and experimental hyperoxia.

    PubMed

    Ekström, Andreas; Brijs, Jeroen; Clark, Timothy D; Gräns, Albin; Jutfelt, Fredrik; Sandblom, Erik

    2016-08-01

    Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring venous oxygen tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5-10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.3-4.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9°C) in hyperoxia, but remained significantly lower than in Biotest fish despite an improved cardiac output due to an elevated stroke volume. Thus, while cardiac oxygen supply appears critical to elevate stroke volume at high temperatures, oxygen limitation may not explain the bradycardia and arrhythmia that occur prior to CTmax Acute thermal tolerance and its thermal plasticity can, therefore, only be partially attributed to cardiac failure from myocardial oxygen limitations, and likely involves limiting factors on multiple organizational levels. PMID:27280433

  5. Influence of domestication process on immune response to repeated emersion stressors in Eurasian perch (Perca fluviatilis, L.).

    PubMed

    Douxfils, J; Lambert, S; Mathieu, C; Milla, S; Mandiki, S N M; Henrotte, E; Wang, N; Dieu, M; Raes, M; Rougeot, C; Kestemont, P

    2014-03-25

    Domestication might be a possible way to reduce the physiological response to long-term stressors and deleterious effects on immunity. The present study aimed to evaluate the chronic immune response induced by repeated emersions and the possible impact of domestication by comparing farmed Eurasian perch with short (F1) and long (F4) captive-life history. In the first experiment, fish were exposed to a single emersion and physiological stress response was measured in the short term to characterize fish sensitivity to the tested stressor. Serum cortisol and glucose elevated within 6h post-stress and splenosomatic index (SSI) decreased within 48h, indicating that the species was affected by emersion stressor. In the second experiment, F1 and F4 generations were submitted to repeated water emersions (3 times/week during 44days). On day 9, 18 and 44, samplings were performed 48h post-stressor to highlight any sustained disruption of immune system. Serum cortisol, glucose, SSI and lysozyme activity were evaluated and serum proteome was analyzed using 2D-DIGE. Any of the tested variables were affected by repeated emersions and proteomic analysis only revealed that alpha-2 macroglobulins (a2Ms) were up-regulated in the serum of stressed individuals. Domestication also resulted in the up-regulation of five a2M isoforms and down-regulation of complement C3 and Ig light chain proteins, independently of any stressor exposure. In conclusion, the results suggested that repeated emersions are not severe stressors for Eurasian perch, probably explaining why domestication had no influence on fish responses. Changes associated with domestication are highly complex and certainly need further investigations.

  6. Cloning and expression of two related connexins from the perch retina define a distinct subgroup of the connexin family.

    PubMed

    O'Brien, J; Bruzzone, R; White, T W; Al-Ubaidi, M R; Ripps, H

    1998-10-01

    We have cloned cDNAs for two closely related connexins (Cx), Cx35 and Cx34.7, from a perch retinal cDNA library. Sequencing of PCR products from genomic DNA revealed that both connexins have an intron 71 bp after the translation initiation site; in Cx35, the intron is 900 bp in length, whereas in Cx34.7 it is approximately 20 kb. Southern blots of genomic DNA suggest that the two connexins represent independent single copy genes. In Northern blots, Cx35 and Cx34.7 transcripts were detected in retina and brain; Cx34.7 also showed a weak signal in smooth muscle (gut) RNA. Antibodies against Cx35 labeled a 30 kDa band on a Western blot of retinal membranes, and in histological sections, the pattern of antibody recognition was consistent with labeling of bipolar cells and unidentified processes in the inner plexiform and nerve fiber layers. When expressed in Xenopus oocytes, Cx35 and Cx34.7 formed homotypic gap junctions, but the junctional conductance between paired oocytes expressing Cx35 was 10-fold greater than that recorded for gap junctional channels formed by Cx34.7. The homotypic gap-junctional channels were closed in a voltage-dependent manner but with relatively weak voltage sensitivity. Heterotypic gap junctions formed by Cx35 and Cx34.7 displayed junctional conductances similar to those of Cx34.7 homotypic pairs and showed a slightly asymmetric current-voltage relationship; the side expressing Cx35 exhibited a higher sensitivity to transjunctional potentials. An analysis of the sequence and gene structure of the connexin family revealed that perch Cx35 and Cx34.7, skate Cx35, and mouse Cx36 constitute a novel gamma subgroup. PMID:9742134

  7. The effect of urbanization in an arid region: Formation of a perched water table that causes environmental damages

    NASA Astrophysics Data System (ADS)

    Karnieli, A.; Issar, A.; Wolf, M.

    1984-03-01

    Construction in a new neighborhood in the israeli town of Dimona, situated in an arid region in the south of the country (150 mm average annual rainfall), resulted in a rise in groundwater levels during the subsequent rainy seasons This caused flooding of shelter basements, soil sliding, and sagging which permanently damaged walls and buildings The neighborhood had been built on continental sands and marls blanketed by loess, on a valley slope near a rocky anticlinal dip-slope Subsurface studies, using piezometer holes and groundwater analyses, revealed the presence of sand lenses alternating with plastic marls, which act as seasonal aquifers with perched water tables Groundwaters obtain high SO{4/-2} and Cl- corrosivity through contact with these nonflushed marls of the Neogene valley fill (Hazeva Formation) The reasons for the rising of groundwater were found to be (a) artificial interference with the natural (pre-construction) drainage system—interception of the hillside runoff by building plots, roads, etc, (b) partial denudation of the loess blanket, increasing the local infiltration and the build-up of local, perched water tables, and (c) corrosion of concrete and steel pipelines, as well as foundations, by prolonged contact with corrosive groundwater, resulting in haphazard but massive leakage Guidelines are proposed for an environmental improvement plan, which would include terracing and planting of the watershed above town to increase evapotranspiration, lowering of the water table by pumping, and diverting the water to suburban parks (groves of saltresistant trees), and replacement of steel and cement pipes by a non-corrodable plastic pipe system

  8. An update of the distribution of selected radiochemical and chemical constituents in perched ground water, Idaho National Laboratory, Idaho, Emphasis 1999-2001

    USGS Publications Warehouse

    Davis, Linda C.

    2006-01-01

    Radiochemical and chemical wastes generated at facilities at the Idaho National Laboratory (INL) were discharged since 1952 to infiltration ponds at the Reactor Technology Complex (RTC) (known as the Test Reactor Area [TRA] until 2005), and the Idaho Nuclear Technology and Engineering Center (INTEC) and buried at the Radioactive Waste Management Complex (RWMC). Disposal of wastewater to infiltration ponds and infiltration of surface water at waste burial sites resulted in formation of perched ground water in basalts and in sedimentary interbeds above the Snake River Plain aquifer. Perched ground water is an integral part of the pathway for waste-constituent migration to the aquifer. The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, maintains ground-water monitoring networks at the INL to determine hydrologic trends, and to monitor the movement of radiochemical and chemical constituents in wastewater discharged from facilities to both perched ground water and the aquifer. This report presents an analysis of water-quality and water-level data collected from wells completed in perched ground water at the INL during 1999-2001, and summarizes historical disposal data and water-level-and water-quality trends. At the RTC, tritium, strontium-90, cesium-137, dissolved chromium, chloride, sodium, and sulfate were monitored in shallow and deep perched ground water. In shallow perched ground water, no tritium was detected above the reporting level. In deep perched ground water, tritium concentrations generally decreased or varied randomly during 1999-2001. During October 2001, tritium concentrations ranged from less than the reporting level to 39.4?1.4 picocuries per milliliter (pCi/mL). Reportable concentrations of tritium during July-October 2001 were smaller than the reported concentrations measured during July-December 1998. Tritium concentrations in water from wells at the RTC were likely affected by: well's distance from the

  9. Ocean optics

    SciTech Connect

    Spinard, R.W.; Carder, K.L.; Perry, M.J.

    1994-12-31

    This volume is the twenty fifth in the series of Oxford Monographs in Geology and Geophysics. The propagation off light in the hydra-atmosphere systems is governed by the integral-differential Radiative Transfer Equation (RTE). Closure and inversion are the most common techniques in optical oceanography to understand the most basic principles of natural variability. Three types of closure are dealt with: scale closure, experimental closure, and instrument closure. The subject is well introduced by Spinard et al. in the Preface while Howard Gordon in Chapter 1 provides an in-depth introduction to the RTE and its inherent problems. Inherent and apparent optical properties are dealt with in Chapter 2 by John Kirk and the realities of optical closure are presented in the following chapter by Ronald Zaneveld. The balance of the papers in this volume is quite varied. The early papers deal in a very mathematical manner with the basics of radiative transfer and the relationship between inherent and optical properties. Polarization of sea water is discussed in a chapter that contains a chronological listing of discoveries in polarization, starting at about 1000 AD with the discovery of dichroic properties of crystals by the Vikings and ending with the demonstration of polarotaxis in certain marine organisms by Waterman in 1972. Chapter 12 on Raman scattering in pure water and the pattern recognition techniques presented in Chapter 13 on the optical effects of large particles may be of relevance to fields outside ocean optics.

  10. A high-mobility group box 1 that binds to DNA, enhances pro-inflammatory activity, and acts as an anti-infection molecule in black rockfish, Sebastes schlegelii.

    PubMed

    Xin-Peng, Zhao; Yong-Hua, Hu; Yong, Liu; Jing-Jing, Wang; Guang-Hua, Wang; Ren-Jie, Wang; Min, Zhang

    2016-09-01

    High-mobility group box (HMGB) 1 is a chromosomal protein that plays critical roles in DNA transcription, replication and repair. In addition, HMGB1 functions as a pro-inflammatory molecule in many vertebrates and invertebrates. In teleosts, very limited studies of HMGB1 have been reported. In this study, we identified a HMGB1 homologue (SsHMGB1) from black rockfish (Sebastes schlegelii) and analyzed its structure, expression and biological function. The open reading frame of SsHMGB1 is 621 bp, with a 5'-untranslated region (UTR) of 62 bp and a 3'-UTR of 645 bp. SsHMGB1 contains two typical HMG boxes and an acidic C-terminal tail. The deduced amino acid sequence of SsHMGB1 shares the highest overall identity (89.4%) with the HMGB1 of Anoplopoma fimbria. The expression of SsHMGB1 occurred in multiple tissues and was highest in the brain. Moreover, the mRNA level of SsHMGB1 in head kidney (HK) macrophages could be induced by Listonella anguillarum in a time-dependent manner. Recombinant SsHMGB1 purified from Escherichia coli (i) bound DNA fragments in a dose-dependent manner; and (ii) induced the expression of cytokines in HK macrophages, including a significant increase in TNF-α activity and enhanced mRNA level of TNF13B and IL-1 β, which are known to be involved in antibacterial defense; moreover, (iii) significantly improved the macrophage bactericidal activity together with reduced pathogen dissemination and replication of bacteria in fish kidney. These results indicated that SsHMGB1 is a novel HMGB1 that possesses apparent immunoregulatory properties and is likely to be involved in fighting bacterial infection. PMID:27492120

  11. Intestinal parasite Acanthocephalus lucii (Acanthocephala) from European perch (Perca fluviatilis) as a bioindicator for lead pollution in the stream "Jevanský potok" near Prague, Czech Republic.

    PubMed

    Jankovská, Ivana; Miholová, Daniela; Petrtýl, Miloslav; Romočuský, Stěpán; Kalous, Lukáš; Vadlejch, Jaroslav; Cadková, Zuzana; Langrová, Iva

    2011-03-01

    Lead concentrations in the tissues of perch and its parasites were determined as mg/kg dw. Lead was found at higher concentrations in the acanthocephalans (11.56) than in different tissues (liver, gonads and muscle with skin and bone) of perch. With respect to fish tissues, the highest concentrations of lead were present in the liver (1.24), followed by the gonads (0.57) whereas the lowest concentrations were in the muscle with skin and bone (0.21). The bioconcentration factors for lead indicated that parasites accumulate metals to a higher degree than fish tissues--lead concentrations in acanthocephalans were 9.32, 19.27 and 55.05 higher than in liver, gonads and muscles of host, respectively.

  12. Depletion of the chloramine-T marker residue, para-toluenesulfonamide, from skin-on fillet tissue of hybrid striped bass, rainbow trout, and yellow perch

    USGS Publications Warehouse

    Meinertz, J.R.; Stehly, G.R.; Greseth, Shari L.; Gaikowski, M.P.; Gingerich, W.H.

    2004-01-01

    Waterborne exposure to n-sodium-n-chloro-p-toluenesulfonamide (chloramine-T) is an effective treatment for controlling fish mortalities caused by bacterial gill disease (BGD). Currently, data are being generated to gain United States Food and Drug Administration (FDA) approval for the use of chloramine-T in aquaculture. As part of the data required for an approval, depletion of the chloramine-T marker residue (para-toluenesulfonamide [p-TSA]) from the edible fillet tissue of exposed fish must be determined. Hybrid striped bass (Morone saxatilis??Morone chrysops; mean weight 357 g), rainbow trout (Oncorhynchus mykiss; mean weight 457 g), and yellow perch (Perca flavescens; mean weight 144 g) were exposed to 20 mg/l of chloramine-T for 60 min on 4 consecutive days (the most aggressive treatment expected for approved use in the United States). Groups of fish (n=15 or 19) were sampled immediately after the last treatment and periodically through 48 or 168 h after the treatment phase. Duplicate subsamples of skin-on fillet tissue from each fish were analyzed for p-TSA. Mean p-TSA concentrations in fillet tissue from fish sampled immediately after the last treatment were 142 ng/g (hybrid striped bass), 97 ng/g (rainbow trout), and 150 ng/g (yellow perch). Mean p-TSA concentrations at terminal sample times were 94 (168 h; hybrid striped bass), 74 (48 h; rainbow trout), and 35 ng/g (168 h; yellow perch). The half-lives of p-TSA in fillet tissue from fish near or at market size were 11.4 (hybrid striped bass), 4.3 (rainbow trout), and 3.2 days (yellow perch).

  13. Safety of oxytetracycline (Terramycin TM-100F) administered in feed to hybrid striped bass, walleyes, and yellow perch

    USGS Publications Warehouse

    Gaikowski, M.P.; Wolf, J.C.; Schleis, S.M.; Gingerich, W.H.

    2003-01-01

    Oxytetracycline (Terramycin TM-100F, a medicated premix containing oxytetracycline at 220 g/kg) is approved in the United States to control certain systemic bacterial diseases of salmon and catfish when fed at a rate of 55-82.5 mg per kilogram of bodyweight per day for 10 d. Although oxytetracycline may also control certain systemic bacterial infections in coolwater or scaled warmwater fish, no safety data for such species are available. Our objective was to determine the safety of oxytetracycline administered in feed at nominal doses of 0, 82.5, 248, or 413 mg??kg-1??d-1 to yellow perch Perca flavescens and hybrid striped bass (striped bass Morone saxatilis x white bass M. chrysops) for 10 d and to walleye Sander vitreus (formerly Stizostedion vitreum) for 20 d. Yellow perch and hybrid striped bass consumed 50% to 100% of the diet, whereas walleye feed consumption was occasionally less than 50% of the diet. Feed or fecal material was present in the gastrointestinal tract of all necropsied walleyes except for one control fish. The single growth effect was that hybrid striped bass offered a nominal dose of 413 mg??kg-1??d-1 were significantly smaller than untreated controls. Oxytetracycline-related histopathological findings were limited to walleyes and were of low severity. The histopathological findings included decreased hematopoietic-lymphopoietic (H&L) tissue in the anterior kidneys, diffuse hyperplasia of the gill filament epithelium, and a decreased prevalence of fish with eosinophilic droplets in their renal tubular epithelial cells. Although the incidence of decreased H&L tissue tended to increase in proportion to oxytetracycline dose, this finding was statistically significant only for fish that received a nominal dose of 413 mg??kg-1??d-1. Given the pathogenicity of the types of bacteria that are controlled by oxytetracycline treatment and the long history of its use in major aquaculture species, the relative risk of the minor oxytetracycline

  14. Change in diel catchability of young-of-year yellow perch associated with establishment of dreissenid mussels

    USGS Publications Warehouse

    Stapanian, Martin A.; Kocovsky, Patrick M.; Adams, Jean V.

    2009-01-01

    1. Non-native mussels have increased water clarity in many lakes and streams in North America and Europe. Diel variation in catchability of some fish species has been linked to visibility during survey trawls (used to measure escapement). 2. Water clarity increased in nearshore areas of western Lake Erie by the early 1990s, following passage of legislation in 1972 to improve water quality (e.g. reduce phosphorus loading) and the invasion of dreissenid mussels (Dreissena spp.) beginning in 1987. 3. We hypothesised that increased water clarity in Lake Erie resulted in decreased catchability of young-of-year (age-0) yellow perch (Perca flavescens Mitchill) during daylight compared to during night. We used a two-tiered modelling approach to test this hypothesis on the ratio (R) of catch per hour (CPH) during night to CPH during daylight in bottom trawl surveys conducted during 1961-2005. 4. First, we examined seven a priori models. The first model, the 'null' model, represented no change in R over time. Three more models tested whether the timing of the change in R was associated with passage of water quality legislation only, dreissenids only (two-period models) and both legislation and dreissenids (three-period models). Three additional models included a 3-year lag before the effects of legislation, dreissenids or both occurred. Secondly, all possible two- and three-period models with a minimum of 2 years per time period were explored a posteriori. The a posteriori procedure determined the temporal transitions to higher R that were best supported by the data, without regard to a priori hypotheses. 5. Night CPH was greater than daylight CPH in 3 of 11 years during 1961-72, in 10 of 15 years during 1973-87, and in 14 of 18 years during 1988-2005. During 1991-2005 night CPH exceeded daylight CPH in all years except one, and night CPH was more than twice daylight CPH in 10 years during this period. 6. The best a priori model had two periods, with a break between 1990 and

  15. Comparative susceptibility among three stocks of yellow perch, Perca flavescens (Mitchill), to viral haemorrhagic septicaemia virus strain IVb from the Great Lakes.

    PubMed

    Olson, W; Emmenegger, E; Glenn, J; Winton, J; Goetz, F

    2013-08-01

    The Great Lakes strain of viral haemorrhagic septicaemia virus IVb (VHSV-IVb) is capable of infecting a wide number of naive species and has been associated with large fish kills in the Midwestern United States since its discovery in 2005. The yellow perch, Perca flavescens (Mitchill), a freshwater species commonly found throughout inland waters of the United States and prized for its high value in sport and commercial fisheries, is a species documented in several fish kills affiliated with VHS. In the present study, differences in survival after infection with VHSV IVb were observed among juvenile fish from three yellow perch broodstocks that were originally derived from distinct wild populations, suggesting innate differences in susceptibility due to genetic variance. While all three stocks were susceptible upon waterborne exposure to VHS virus infection, fish derived from the Midwest (Lake Winnebago, WI) showed significantly lower cumulative % survival compared with two perch stocks derived from the East Coast (Perquimans River, NC and Choptank River, MD) of the United States. However, despite differences in apparent susceptibility, clinical signs did not vary between stocks and included moderate-to-severe haemorrhages at the pelvic and pectoral fin bases and exophthalmia. After the 28-day challenge was complete, VHS virus was analysed in subsets of whole fish that had either survived or succumbed to the infection using both plaque assay and quantitative PCR methodologies. A direct correlation was identified between the two methods, suggesting the potential for both methods to be used to detect virus in a research setting. PMID:23305522

  16. Ocean Current Boundry, North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This view of the ocean current boundry between the Gulf Stream of the North Atlantic Ocean and the coastal currents off the eastern seaboard of North America (43.5N, 65.5W), is an excellent study in ocean dynamics. The warm waters of the Gulf Stream are clearly visible as a dynamic rapidly flowing current with many internal wave patterns and a rougher surface versus the cooler and less active coastal shelf waters having a smoother surface.

  17. Studying ocean acidification in the Arctic Ocean

    USGS Publications Warehouse

    Robbins, Lisa

    2012-01-01

    The U.S. Geological Survey (USGS) partnership with the U.S. Coast Guard Ice Breaker Healey and its United Nations Convention Law of the Sea (UNCLOS) cruises has produced new synoptic data from samples collected in the Arctic Ocean and insights into the patterns and extent of ocean acidification. This framework of foundational geochemical information will help inform our understanding of potential risks to Arctic resources due to ocean acidification.

  18. {sup 32}P-postlabeling analysis of DNA adducts in wild perch (Perca fluviatilis) and northern pike (Esox lucius)

    SciTech Connect

    Ericson, G.; Liewenborg, B.; Balk, L.

    1995-12-31

    Several previous studies have demonstrated a correlation between high concentrations of sediment-associated contaminants and elevated levels of aromatic/hydrophobic DNA adduct levels in the liver of benthic fish species. In the present study DNA adducts was analyzed in coastal populations of perch (Perca fluviatilis) and northern pike (Esox lucius). Fish were sampled from four different sites in a gradient from a heavily industrialized area at the Swedish Baltic coast. For comparison, fish were also caught in a reference area with no main industries and comparatively low levels of contaminants of anthropogenic origin. DNA was extracted from liver and several extrahepatic tissues and DNA adducts were analyzed by the nuclease PI version of the {sup 32}P-postlabeling assay. The autoradiograms derived from DNA of fish from the contaminated sites showed several adduct spots not visible on the autoradiograms derived from fish from the reference area. Total adduct levels were significantly elevated in several tissues in fish from contaminated sites compared to the reference area. Species and tissue-specific differences in adduct levels and the use of {sup 32}P-postlabeling analysis of DNA adducts as a biomarker to monitor the presence and effects of genotoxic chemicals in the aquatic environment are discussed.

  19. Exploring spatial distributions of larval yellow perch Perca flavescens, bluegill Lepomis macrochirus and their prey in relation to wind.

    PubMed

    Kaemingk, M A; Jolley, J C; Willis, D W; Graeb, B D S

    2011-04-01

    The objectives of the present study were to determine if spatial differences existed between zooplankton, larval yellow perch Perca flavescens and bluegill Lepomis macrochirus (<13 mm total length, L(T)) in Pelican Lake (332 ha), NE, U.S.A. It was hypothesized that wind could act as a transport mechanism for larval fishes in this shallow lake, because strong winds are common at this geographic location. Potential spatial differences were explored, relating to zooplankton densities, size structure and densities of larval P. flavescens and L. macrochirus. Density differences (east v. west side of the lake) were detected for small- (two occasions), medium- (two occasions) and large-sized (one occasion) L. macrochirus larvae. No density differences were detected for small P. flavescens larvae; however, densities of medium- and large-sized P. flavescens were each higher on the west side of the lake on two occasions. There was no evidence that larval P. flavescens and L. macrochirus distributions were related to wind because they were not associated with large wind events. Likewise, large wind event days did not result in any detectable spatial differences of larval P. flavescens and L. macrochirus densities. There appeared to be no spatial mismatch between larval densities and associated prey in the years examined. Thus, wind was not apparently an influential mechanism for zooplankton and larval P. flavescens and L. macrochirus transport within Pelican Lake, and spatial differences in density may instead be related to vegetation and habitat complexities or spawning locations within this shallow lake.

  20. Late-Pleistocene and Holocene remains of Hysterocarpus traski (Tule Perch) from Clear Lake, California, and inferred Holocene temperature fluctuations

    USGS Publications Warehouse

    Casteel, R.W.; Adam, D.P.; Sims, J.D.

    1977-01-01

    The remains of scales of Hysterocarpus traski Gibbons (Tule perch) were found throughout a 27.44-m core from Clear Lake. Most scales occurred between the mud surface and deposits approximately 11,000 years old. Changes in growth rates of the animals were examined by measuring scale annuli and applying an empirically established regression of fish length on scale radius. The data indicate a pattern of accelerating growth rates, reaching a peak between {reversed tilde equals}4000 and 2800 BP. After {reversed tilde equals}2800 BP, growth rates decline markedly. Because the growth rates of these animals are essentially dependent on temperature, the changes observed in the patterns of growth probably reflect changes in climate in the northern Coast Range. The general pattern of inferred temperature increase during the early and middle Holocene, ending between {reversed tilde equals}4000 and 2800 BP, is consistent with evidence from tree-line studies and palynology indicating higher temperatures in parts of the western United States during this period. ?? 1977.

  1. The role of continental shelf width in determining freshwater phylogeographic patterns in south-eastern Australian pygmy perches (Teleostei: Percichthyidae).

    PubMed

    Unmack, Peter J; Hammer, Michael P; Adams, Mark; Johnson, Jerald B; Dowling, Thomas E

    2013-03-01

    Biogeographic patterns displayed by obligate freshwater organisms are intimately related to the nature and extent of connectivity between suitable habitats. Two of the more significant barriers to freshwater connections are seawater and major drainage divides. South-eastern Australia provides a contrast between these barriers as it has discrete areas that are likely influenced to a greater or lesser extent by each barrier type. We use continental shelf width as a proxy for the potential degree of river coalescence during low sea levels. Our specific hypothesis is that the degree of phylogeographic divergence between coastal river basins should correspond to the continental shelf width of each region. This predicts that genetic divergences between river basins should be lowest in regions with a wider continental shelf and that regions with similar continental shelf width should have similar genetic divergences. Pygmy perches (Nannoperca australis and Nannoperca 'flindersi') in south-eastern Australia provide an ideal opportunity to test these biogeographic hypotheses. Phylogeographic patterns were examined based on range-wide sampling of 82 populations for cytochrome b and 23 polymorphic allozyme loci. Our results recovered only limited support for our continental shelf width hypothesis, although patterns within Bass clade were largely congruent with reconstructed low sea-level drainage patterns. In addition, we identified several instances of drainage divide crossings, typically associated with low elevational differences. Our results demonstrate high levels of genetic heterogeneity with important conservation implications, especially for declining populations in the Murray-Darling Basin and a highly restricted disjunct population in Ansons River, Tasmania.

  2. Investigation of the Potential for 90Sr Immobilization in INTEC Perched Water via Microbially Facilitated Calcite Precipitation

    SciTech Connect

    Yoshiko Fujita; Karen E. Wright; William A. Smith

    2006-10-01

    The goal of this work is to evaluate the applicability of a biogeochemical sequestration approach for remediation of 90Sr contamination in perched water zones underlying the Idaho Nuclear Technology and Engineering Center (INTEC). The approach is based on the accelerated co-precipitation of the contaminant in calcite, where the acceleration is catalyzed by the microbial urea hydrolysis. We have previously demonstrated the potential for this remediation mechanism to immobilize strontium. Urea hydrolysis promotes calcite precipitation (and trace metal co-precipitation) by increasing groundwater pH and alkalinity. Ureolysis is catalyzed by the urease enzyme, which is produced by many environmental microorganisms. In the Snake River Plain Aquifer, which is saturated with respect to calcite, any co-precipitated 90Sr should be effectively sequestered over the long-term, even after return to pre-manipulation conditions. Another advantage of the ureolysis approach is that the NH4+ ions produced by the reaction can exchange with cations sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture via a more stable mechanism (co-precipitation rather than adsorption).

  3. Genetic damage induced by lead chloride in different tissues of fresh water climbing perch Anabas testudineus (Bloch).

    PubMed

    Ahmed, Md Kawser; Parvin, Elora; Arif, Mohammad; Islam, Md Monirul; Akter, Mosammat Salma; Khan, Mohammad Shahneawz

    2011-11-01

    The present investigation was undertaken to study the induction of DNA damage by lead chloride (PbCl(2)) in freshwater climbing perch Anabas testudineus using alkaline single cell gel electrophoresis (comet assay). Based on the LC(50) values of lead chloride of A. testudineus three different concentrations viz., 0.1, 1.0 and 2.0 mg/L were selected to expose fish. The DNA damage was observed in the gill, kidney and liver tissue as the percentage of DNA in comet tails and comet heads in the tissue of the exposed fish. DNA damage at different concentrations showed sensitivity to particular tissue. The liver tissue exhibited significantly (p < 0.01) higher DNA damage, followed by kidney and gill. However, the DNA damage was found to be dose dependent; at 2 mg/L of PbCl(2) the tail and head DNA of liver tissue were 57.84% and 39.49%, in kidney tissue the values were 52.36% and 44.97% whereas in gill tissue the values were 48.86% and 48.96% respectively. The current study explored the utility of the comet assay for in vivo laboratory studies using A. testudineus species for screening the genotoxic potential of lead chloride.

  4. Selection of perching site background color by Hamadryas feronia (Lepidoptera: Nymphalidae) in Costa Rica: implications for industrial melanism.

    PubMed

    Murillo-Hiller, Luis Ricardo

    2012-09-01

    Observations of the increased frequency of melanic forms in moths of the genus Biston in Great Britain after the industrial revolution lead to the development of the theory of Industrial Melanism. Nonetheless, arguments against that interpretation of the experimental evidence have polarized acceptance of the concept. New evidence based on diurnal butterflies is more credible because it involves behavior that can be seen in action, during daylight, and because the natural history of the selected species is well known. An experiment was carried out in which three substrate colors (white, black, and gray) were employed to test the landing preferences of Hamadryas feronia. A marked preference was observed for landing on white and gray, and a chi-square (N=644 tests) showed evidence of a preference by males to land on white, and for females to land on gray. Black was rejected perhaps because it provides very little background matching with the butterfly's colors. The butterfly habit of perching selectively on particular color substrates is a genetically fixed behavior, where the males possibly choose white as a tactic to be noticed by females and attract them, whereas females prefer gray to enhance crypsis and avoid attracting predators.

  5. Larval dispersal underlies demographically important inter-system connectivity in a Great Lakes yellow perch (Perca flavescens) population

    USGS Publications Warehouse

    Brodnik, Reed M.; Fraker, Michael E.; Anderson, Eric J.; Carreon-Martinez, Lucia; DeVanna, Kristen M.; Heath, Dan D.; Reichert, Julie M.; Roseman, Edward F.; Ludsin, Stuart A.

    2016-01-01

    Ability to quantify connectivity among spawning subpopulations and their relative contribution of recruits to the broader population is a critical fisheries management need. By combining microsatellite and age information from larval yellow perch (Perca flavescens) collected in the Lake St. Clair – Detroit River system (SC-DRS) and western Lake Erie with a hydrodynamic backtracking approach, we quantified subpopulation structure, connectivity, and contributions of recruits to the juvenile stage in western Lake Erie during 2006-2007. After finding weak (yet stable) genetic structure between the SC-DRS and two western Lake Erie subpopulations, microsatellites also revealed measurable recruitment of SC-DRS larvae to the juvenile stage in western Lake Erie (17-21% during 2006-2007). Consideration of pre-collection larval dispersal trajectories, using hydrodynamic backtracking, increased estimated contributions to 65% in 2006 and 57% in 2007. Our findings highlight the value of complementing subpopulation discrimination methods with hydrodynamic predictions of larval dispersal by revealing the SC-DRS as a source of recruits to western Lake Erie and also showing that connectivity through larval dispersal can affect the structure and dynamics of large-lake fish populations.

  6. Effect of high pressure processing on textural and microbiological quality of pink perch (Nemipterus japonicus) sausage during chilled storage

    NASA Astrophysics Data System (ADS)

    Kunnath, Sarika; Panda, Satyen Kumar; Jaganath, Bindu; Gudipati, Venkateshwarlu

    2015-10-01

    The non-thermal high pressure (HP) processing was studied on fish sausage to enhance the quality during chilled storage. Pink perch (Nemipterus japonicus) sausages, packed in poly amide casing under vacuum were subjected to 400, 500 and 600 MPa pressures (dwell time: 10 min and ramp rate: 300 MPa/min) and compared with heat-set samples for physico-chemical and microbial quality parameters. Pressurized samples formed softer and glossier gels with a slight reduction in water-holding capacity. HP made the texture of sausage softer, cohesive and less chewy and gummier than heat-treated ones. Folding test seen higher acceptance values in samples treated at 500 and 600 MPa, during storage. Maximum log reduction in microbial count was observed in 600 MPa immediately, and significant difference in cooked and pressurized sausages was seen only up to 7th day. This revealed the potential application of HP in replacing conventional heat treatment for sausages preparation with enhanced shelf-life.

  7. Feeding Glycyrrhiza glabra (liquorice) and Astragalus membranaceus (AM) alters innate immune and physiological responses in yellow perch (Perca flavescens).

    PubMed

    Elabd, Hiam; Wang, Han-Ping; Shaheen, Adel; Yao, Hong; Abbass, Amany

    2016-07-01

    The current work assessed the potential immunomodulatory and growth-promoting effects of Astragalus membranaceus (AM) and Glycyrrhiza glabra (liquorice) in Yellow perch (Perca flavescens). In this regard, fish with an average weight of 31 ± 1.0 g were divided into five groups, and fed daily with an additive-free basal diet (control); 1, 2, and 3% (w/w) Glycyrrhiza glabra, and the fifth diet was incorporated with a combination of 1% G. glabra-AM for a four-week period. Immunological, biochemical and growth parameters were measured; and sub-groups of fish were exposed to 1-week starvation. The results showed that incorporating AM and liquorice in the diet significantly improved Immunological [superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), Lipid peroxidase (LPx) and lysozyme activities], biochemical [Aspartate Aminotransferase (AST) and Alanine Transaminase (ALT) activities; and glucose and cortisol concentrations] and growth performance parameters [body mass gain (BMG), specific growth rate (SGR), length, condition factor (K) and feed conversion ratio (FCR)]. In addition, markedly up-regulated the expression of related genes [Insulin-Like Growth Factor-1 (IGF-1), Serum amyloid A (SAA), Complement Component C3 (CCC3), Alpha 2 Macroglobulin (A2M), SOD and GPx] in treated fish groups compared to the control. Conclusively, feeding AM and liquorice diets significantly increased (P < 0.05) growth performance, antioxidant and immune response profiles throughout the entire experiment, suggesting their beneficial rule as natural anti-stress agents.

  8. Comparative study of lead accumulation in different organs of perch (Perca fluviatilis) and its intestinal parasite Acanthocephalus lucii

    SciTech Connect

    Sures, B.; Taraschewski, H.; Jackwerth, E. )

    1994-02-01

    Lead is known as an important aquatic contaminant with different toxic effects on various organisms. Considerable data are available on lead in aquatic ecosystems including water, sediments, fishes and invertebrates. Until now, no quantitative investigations have been published comparing the heavy metal (Pb, Cd, Hg) content in parasites with that in their final or intermediate hosts, although such parasites are very prevalent in many fish and invertebrate populations. Only Brown and Pascoe (1989) reported that the amphipod Gammarus pulex parasitized with the acanthocephalan Pomphorhynchus laevis was two or three times more sensitive to cadmium at low exposure concentrations (2.1 [mu]g 1[sup [minus]1]) than uninfected conspecifics. The objective of the present study was to combine trace analytical and parasitological methods to investigate lead concentrations in different tissues (muscle, liver and intestine) of perch (Perca fluviatilis) and in the palaeacanthocephalan Acanthocephalus lucii parasitizing the intestine of these fishes. The fish were caught in the river Ruhr which drains the densely populated and industrialized Ruhr-district. 14 refs., 2 tabs.

  9. Catchment-scale conservation units identified for the threatened Yarra pygmy perch (Nannoperca obscura) in highly modified river systems.

    PubMed

    Brauer, Chris J; Unmack, Peter J; Hammer, Michael P; Adams, Mark; Beheregaray, Luciano B

    2013-01-01

    Habitat fragmentation caused by human activities alters metapopulation dynamics and decreases biological connectivity through reduced migration and gene flow, leading to lowered levels of population genetic diversity and to local extinctions. The threatened Yarra pygmy perch, Nannoperca obscura, is a poor disperser found in small, isolated populations in wetlands and streams of southeastern Australia. Modifications to natural flow regimes in anthropogenically-impacted river systems have recently reduced the amount of habitat for this species and likely further limited its opportunity to disperse. We employed highly resolving microsatellite DNA markers to assess genetic variation, population structure and the spatial scale that dispersal takes place across the distribution of this freshwater fish and used this information to identify conservation units for management. The levels of genetic variation found for N. obscura are amongst the lowest reported for a fish species (mean heterozygosity of 0.318 and mean allelic richness of 1.92). We identified very strong population genetic structure, nil to little evidence of recent migration among demes and a minimum of 11 units for conservation management, hierarchically nested within four major genetic lineages. A combination of spatial analytical methods revealed hierarchical genetic structure corresponding with catchment boundaries and also demonstrated significant isolation by riverine distance. Our findings have implications for the national recovery plan of this species by demonstrating that N. obscura populations should be managed at a catchment level and highlighting the need to restore habitat and avoid further alteration of the natural hydrology.

  10. Catchment-Scale Conservation Units Identified for the Threatened Yarra Pygmy Perch (Nannoperca obscura) in Highly Modified River Systems

    PubMed Central

    Brauer, Chris J.; Unmack, Peter J.; Hammer, Michael P.; Adams, Mark; Beheregaray, Luciano B.

    2013-01-01

    Habitat fragmentation caused by human activities alters metapopulation dynamics and decreases biological connectivity through reduced migration and gene flow, leading to lowered levels of population genetic diversity and to local extinctions. The threatened Yarra pygmy perch, Nannoperca obscura, is a poor disperser found in small, isolated populations in wetlands and streams of southeastern Australia. Modifications to natural flow regimes in anthropogenically-impacted river systems have recently reduced the amount of habitat for this species and likely further limited its opportunity to disperse. We employed highly resolving microsatellite DNA markers to assess genetic variation, population structure and the spatial scale that dispersal takes place across the distribution of this freshwater fish and used this information to identify conservation units for management. The levels of genetic variation found for N. obscura are amongst the lowest reported for a fish species (mean heterozygosity of 0.318 and mean allelic richness of 1.92). We identified very strong population genetic structure, nil to little evidence of recent migration among demes and a minimum of 11 units for conservation management, hierarchically nested within four major genetic lineages. A combination of spatial analytical methods revealed hierarchical genetic structure corresponding with catchment boundaries and also demonstrated significant isolation by riverine distance. Our findings have implications for the national recovery plan of this species by demonstrating that N. obscura populations should be managed at a catchment level and highlighting the need to restore habitat and avoid further alteration of the natural hydrology. PMID:24349405

  11. Molecular cloning and mRNA expression analysis of interleukin-8 gene in Japanese sea perch (Lateolabrax japonicus).

    PubMed

    Qiu, Lihua; Zhang, Hanhua; Yang, Keng; Jiang, Shigui

    2009-05-01

    Interleukin-8 (IL-8), the first known chemokine, is a CXC chemokine, which is cable of attracting neutrophils and inducing them to release lysozomal enzymes, triggering the respiratory burst. In the present study, the cDNA of an IL-8 was cloned from Japanese sea perch Lateolabrax japonicus (designated LjIL-8) by homology cloning and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of LjIL-8 consisted of 803 nucleotides with a canonical polyadenylation signal sequence AATAAA and a poly(A) tail, and an open reading frame (ORF) of 300 bp encoding a polypeptide of 99 amino acid residues with a predicted molecular weight of 6.6 kDa. The high identity of LjIL-8 with IL-8 in other organisms indicated that LjIL-8 should be a new member of the IL-8 family. By fluorescent quantitative real-time PCR, mRNA transcript of LjIL-8 was detectable in all the examined tissues with higher level in spleen and head-kidney. The temporal expression of LjIL-8 mRNA in the spleen was up-regulated by lipopolyssacharide (LPS) stimulation and reached the maximum level at 6 h post-stimulation, and then dropped back to the original level gradually. These results indicated that LjIL-8 was a constitutive and inducible acute-phase protein that perhaps involved in the immune defense of L. japonicus.

  12. The Ocean Literacy Campaign

    NASA Astrophysics Data System (ADS)

    Schoedinger, S. E.; Strang, C.

    2008-12-01

    "Ocean Literacy is an understanding of the ocean's influence on you and your influence on the ocean." This simple statement captures the spirit of a conceptual framework supporting ocean literacy (COSEE et al., 2005). The framework comprises 7 essential principles and 44 fundamental concepts an ocean literate person would know (COSEE et al., 2005). The framework is the result of an extensive grassroots effort to reach consensus on (1) a definition for ocean literacy and (2) an articulation of the most important concepts to be understood by ocean-literate citizen (Cava et al., 2005). In the process of reaching consensus on these "big ideas" about the ocean, what began as a series of workshops has emerged as a campaign "owned" by an ever-expanding community of individuals, organizations and networks involved in developing and promoting the framework. The Ocean Literacy Framework has provided a common language for scientists and educators working together and serves as key guidance for the ocean science education efforts. This presentation will focus on the impact this Ocean Literacy Campaign has had to date as well as efforts underway to provide additional tools to enable educators and educational policy makers to further integrate teaching and learning about the ocean and our coasts into formal K-12 education and informal education. COSEE, National Geographic Society, NOAA, College of Exploration (2005). Ocean Literacy: The Essential Principles of Ocean Sciences Grades K-12, a jointly published brochure, URL: http://www.coexploration.org/oceanliteracy/documents/OceanLitChart.pdf Cava, F., S. Schoedinger , C. Strang, and P. Tuddenham (2005). Science Content and Standards for Ocean Literacy: A Report on Ocean Literacy, URL: http://www.coexploration.org/oceanliteracy/documents/OLit2004-05_Final_Report.pdf.

  13. Harvesting the Ocean: 1. The Ocean.

    ERIC Educational Resources Information Center

    Caton, Albert, Ed.; And Others

    This booklet is the first in a series of three interdisciplinary units which focus specifically on the Pacific Ocean and its surrounding countries. The booklet, designed for lower secondary students, provides an introduction to the ocean environment such that students can understand the physical factors underlying issues raised by the other two…

  14. Ocean acidification in the Western Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Cai, W.; Chen, B.; Chen, L.

    2011-12-01

    We report carbonate chemistry and ocean acidification status in the western Arctic Ocean from 65-88οN based on data collected in summer 2008 and 2010. In the marginal seas, surface waters have high pH and high carbonate saturation state (Ω) due to intensive biological uptake of CO2. In the southern Canada Basin, surface waters have low pH and low Ω due to the uptake of atmospheric CO2 and sea-ice melt. In the northern Arctic Ocean basin, there is no serious ocean acidification in surface water due to heavy ice-coverage but pH and Ω in the subsurface waters at the oxygen minimum and nutrient maximum zone (at 100-150 m) are low due mostly to respiration-derived CO2 and an increased biological production and export in surface waters. Such multitude responses of ocean carbonate chemistry (northern vs. southern basin, basins vs. margins, and surface vs. subsurface) to climate changes are unique to the Arctic Ocean system. We will explore biogeochemical control mechanisms on carbonate chemistry and ocean acidification in the Arctic Ocean environments in the context of recent warming and sea-ice retreat.

  15. 77 FR 22523 - Safety Zone; 2012 Ocean City Air Show; Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2012 Ocean City Air Show; Atlantic Ocean... proposes establishing a safety zone on the navigable waters of the Atlantic Ocean in Ocean City, MD. This..., 2012, the Town of Ocean City will host an air show event over the Atlantic Ocean in Ocean City, MD....

  16. People and Oceans.

    ERIC Educational Resources Information Center

    NatureScope, 1988

    1988-01-01

    Discusses people's relationship with oceans, focusing on ocean pollution, use, and protective measures of the sea and its wildlife. Activities included are "Mythical Monsters"; "Globetrotters"; "Plastic in the Sea"; and "Sea of Many Uses." (RT)

  17. Ocean Robotic Networks

    SciTech Connect

    Schofield, Oscar

    2012-05-23

    We live on an ocean planet which is central to regulating the Earth’s climate and human society. Despite the importance of understanding the processes operating in the ocean, it remains chronically undersampled due to the harsh operating conditions. This is problematic given the limited long term information available about how the ocean is changing. The changes include rising sea level, declining sea ice, ocean acidification, and the decline of mega fauna. While the changes are daunting, oceanography is in the midst of a technical revolution with the expansion of numerical modeling techniques, combined with ocean robotics. Operating together, these systems represent a new generation of ocean observatories. I will review the evolution of these ocean observatories and provide a few case examples of the science that they enable, spanning from the waters offshore New Jersey to the remote waters of the Southern Ocean.

  18. Perched Lava Pond Complex on South Rift of Axial Volcano Revealed in AUV Mapping

    NASA Astrophysics Data System (ADS)

    Paduan, J. B.; Clague, D. A.; Caress, D. W.; Thomas, H. J.

    2013-12-01

    -like structures and jumbled sheet flows on the floors suggest the eruption was on-going when the ponds emptied. 14C-dating of foraminifera from basal sediments on the pond floors gives a minimum age for the ponds of ~1500 years, which is older than any of the surface flows in Axial's summit caldera. Limu o Pele was abundant. Glass contents of the recovered lavas are 7.6 to 8.0 wt% MgO with few exceptions, and other than being plagioclase-phyric, the chemistry is similar to the majority of lavas at the summit. Lava samples from the floors of several ponds have a few tenths of a weight percent lower MgO than the nearby levees, suggesting the pond's molten interior or resupplied lavas had some time to cool. The varying levee rim heights and abundance of ponds in the vicinity suggest this type of activity occurred many times in this area, but it is an unusual eruption style for mid-ocean ridges. Another lava pond complex with even higher levees occurs on the north rift of Axial Volcano. Formation of these ponds requires long-lived, steady, moderate-eruption-rate lava effusion on nearly horizontal seafloor and may occur only on deep distal rift zones of central volcanoes.

  19. Activity Book: Ocean Ecology.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    Presents a collection of activities to help elementary students study ocean ecology. The activities have students investigate ocean inhabitants, analyze animal adaptations, examine how temperature and saltiness affect ocean creatures, and learn about safeguarding the sea. Student pages offer reproducible learning sheets. (SM)

  20. The Physical Ocean.

    ERIC Educational Resources Information Center

    NatureScope, 1988

    1988-01-01

    Examines the physical properties of the ocean (including the composition of seawater; waves, currents, and tides) and the topography of the ocean floor. Included are (1) activities on oceans, saltwater, and the sea floor; and (2) questions, and a puzzle which can be copied. (Author/RT)

  1. Ocean Drilling Simulation Activity.

    ERIC Educational Resources Information Center

    Telese, James A.; Jordan, Kathy

    The Ocean Drilling Project brings together scientists and governments from 20 countries to explore the earth's structure and history as it is revealed beneath the oceans' basins. Scientific expeditions examine rock and sediment cores obtained from the ocean floor to learn about the earth's basic processes. The series of activities in this…

  2. Evaluating fishery rehabilitation under uncertainty: A bioeconomic analysis of quota management for the Green Bay yellow perch fishery

    USGS Publications Warehouse

    Johnson, B.L.; Milliman, S.R.; Bishop, R.C.; Kitchell, J.F.

    1992-01-01

    The fishery for yellow perch Perca flavescens in Green Bay, Lake Michigan, is currently operating under a rehabilitation plan based on a commercial harvest quota. We developed a bioeconomic computer model that included links between population density and growth, recruitment, and fishing effort for this fishery. Random variability was included in the stock-recruitment relation and in a simulated population assessment. We used the model in an adaptive management framework to evaluate the effects of the rehabilitation plan on both commercial and sport fisheries and to search for ways to improve the plan. Results indicate that the current quota policy is a member of a set of policies that would meet most management goals and increase total value of the fishery. Sensitivity analyses indicate that this conclusion is robust over a wide range of biological conditions. We predict that commercial fishers will lose money relative to the baseline condition, but they may receive other benefits from the elimination of the common-property nature of the fishery. The prospect exists for managing variability in harvest and stock size and for maximizing economic returns in the fishery, but more information is required, primarily on sportfishing effort dynamics and angler preferences. Stock-recruitment relations, density dependence of growth, and dynamics of sportfishing effort are the primary sources of uncertainty limiting the precision of our predictions. The current quota policy is about as good as other policies at reducing this uncertainty and appears, overall, to be one of the best choices for this fishery. The analytical techniques used in this study were primarily simple, heuristic approaches that could be easily transferred to other studies.

  3. Feeding Glycyrrhiza glabra (liquorice) and Astragalus membranaceus (AM) alters innate immune and physiological responses in yellow perch (Perca flavescens).

    PubMed

    Elabd, Hiam; Wang, Han-Ping; Shaheen, Adel; Yao, Hong; Abbass, Amany

    2016-07-01

    The current work assessed the potential immunomodulatory and growth-promoting effects of Astragalus membranaceus (AM) and Glycyrrhiza glabra (liquorice) in Yellow perch (Perca flavescens). In this regard, fish with an average weight of 31 ± 1.0 g were divided into five groups, and fed daily with an additive-free basal diet (control); 1, 2, and 3% (w/w) Glycyrrhiza glabra, and the fifth diet was incorporated with a combination of 1% G. glabra-AM for a four-week period. Immunological, biochemical and growth parameters were measured; and sub-groups of fish were exposed to 1-week starvation. The results showed that incorporating AM and liquorice in the diet significantly improved Immunological [superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), Lipid peroxidase (LPx) and lysozyme activities], biochemical [Aspartate Aminotransferase (AST) and Alanine Transaminase (ALT) activities; and glucose and cortisol concentrations] and growth performance parameters [body mass gain (BMG), specific growth rate (SGR), length, condition factor (K) and feed conversion ratio (FCR)]. In addition, markedly up-regulated the expression of related genes [Insulin-Like Growth Factor-1 (IGF-1), Serum amyloid A (SAA), Complement Component C3 (CCC3), Alpha 2 Macroglobulin (A2M), SOD and GPx] in treated fish groups compared to the control. Conclusively, feeding AM and liquorice diets significantly increased (P < 0.05) growth performance, antioxidant and immune response profiles throughout the entire experiment, suggesting their beneficial rule as natural anti-stress agents. PMID:27129627

  4. Perching and Interflow Occurrence over a Shallow Argillic Layer in a Low Relief Upper Coastal Plan Watershed

    NASA Astrophysics Data System (ADS)

    Du, E.; Jackson, C. R.; Vache, K. B.; Hopp, L.

    2011-12-01

    On a first order, low relief, forested watershed at the Savannah River Site (SRS) in the Upper Coastal Plain of South Carolina, we are monitoring soil moisture, shallow piezometric behavior, interflow, groundwater dynamics, and streamflow to identify critical flow pathways, characterize system behavior, and parameterize distributed hydrologic models for estimating effects of bioenergy feedstock production. A mix of pine and hardwoods reforested from agricultural land abandoned in 1950 cover the watershed. Sandy topsoils overlie a low permeability sandy clay loam argillic layer on gently rolling hills with flat forested wetland valleys accommodating slow moving intermittent streamflow. Depths to clay and the saturated hydraulic conductivity (Ksat) of the clay are highly variable. Compact constant head permeameter measurements vary over six orders of magnitude, with anomalies featuring conductivities greater than those observed in the topsoils. Perching on the clay horizon was common. Although the geometric mean and median Ksat of the argillic layer are low (Ksat as low as 0.001 cm/hr), interflow only occurs with large storms on wet soils apparently due to clay anomalies, low relief topography, and relatively high active storage within the topsoil. Fine scale detection of depth to clay (2 by 1m) implies that delineation of subsurface topography may help to understand the flow behavior and destination. Wells records and saturated valley survey show that streamflow dynamics is poorly related to interflow but mainly controlled by seasonal groundwater dynamics. Streamflow analyses at different scales indicate hyporheic flow contribute significantly to the overall water budget at 1st order streams while the groundwater bypass is relatively small at downstream gauges. The next step is to integrate temporal series data of streamflow, soil moisture, groundwater, and interflow to develop and parameterized hydrologic models.

  5. Groundwater recharge assessment at local and episodic scale in a soil mantled perched karst aquifer in southern Italy

    NASA Astrophysics Data System (ADS)

    Allocca, V.; De Vita, P.; Manna, F.; Nimmo, J. R.

    2015-10-01

    Groundwater recharge assessment of karst aquifers, at various spatial and temporal scales, is a major scientific topic of current importance, since these aquifers play an essential role for both socio-economic development and fluvial ecosystems. In this study, groundwater recharge was estimated at local and episodic scales in a representative perched karst aquifer in a region of southern Italy with a Mediterranean climate. The research utilized measurements of precipitation, air temperature, soil water content, and water-table depth, obtained in 2008 at the Acqua della Madonna test area (Terminio Mount karst aquifer, Campania region). At this location the aquifer is overlain by ash-fall pyroclastic soils. The Episodic Master Recession (EMR) method, an improved version of the Water Table Fluctuation (WTF) method, was applied to estimate the amount of recharge generated episodically by individual rainfall events. The method also quantifies the amount of precipitation generating each recharge episode, thus permitting calculation of the Recharge to the Precipitation Ratio (RPR) on a storm-by-storm basis. Depending on the seasonally varying air temperature, evapotranspiration, and precipitation patterns, calculated values of RPR varied between 35% and 97% among the individual episodes. A multiple linear correlation of the RPR with both the average intensity of recharging rainfall events and the antecedent soil water content was calculated. Given the relatively easy measurability of precipitation and soil water content, such an empirical model would have great hydrogeological and practical utility. It would facilitate short-term forecasting of recharge in karst aquifers of the Mediterranean region and other aquifers with similar hydrogeological characteristics. By establishing relationships between the RPR and climate-dependent variables such as average storm intensity, it would facilitate prediction of climate-change effects on groundwater recharge. The EMR methodology

  6. The role of continental shelf width in determining freshwater phylogeographic patterns in south-eastern Australian pygmy perches (Teleostei: Percichthyidae).

    PubMed

    Unmack, Peter J; Hammer, Michael P; Adams, Mark; Johnson, Jerald B; Dowling, Thomas E

    2013-03-01

    Biogeographic patterns displayed by obligate freshwater organisms are intimately related to the nature and extent of connectivity between suitable habitats. Two of the more significant barriers to freshwater connections are seawater and major drainage divides. South-eastern Australia provides a contrast between these barriers as it has discrete areas that are likely influenced to a greater or lesser extent by each barrier type. We use continental shelf width as a proxy for the potential degree of river coalescence during low sea levels. Our specific hypothesis is that the degree of phylogeographic divergence between coastal river basins should correspond to the continental shelf width of each region. This predicts that genetic divergences between river basins should be lowest in regions with a wider continental shelf and that regions with similar continental shelf width should have similar genetic divergences. Pygmy perches (Nannoperca australis and Nannoperca 'flindersi') in south-eastern Australia provide an ideal opportunity to test these biogeographic hypotheses. Phylogeographic patterns were examined based on range-wide sampling of 82 populations for cytochrome b and 23 polymorphic allozyme loci. Our results recovered only limited support for our continental shelf width hypothesis, although patterns within Bass clade were largely congruent with reconstructed low sea-level drainage patterns. In addition, we identified several instances of drainage divide crossings, typically associated with low elevational differences. Our results demonstrate high levels of genetic heterogeneity with important conservation implications, especially for declining populations in the Murray-Darling Basin and a highly restricted disjunct population in Ansons River, Tasmania. PMID:23398527

  7. Emerging ocean issues

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    1984-04-01

    Seven topics have been identified by the topics committee of the Year of the Ocean as focal points of discussions as part of the Year of the Ocean celebration. The Year of the Ocean (Eos, June 19, 1984, p. 402, and April 24, 1984, p. 326) is a year-long commemoration and celebration, begun on July 1, of the oceans. The commemoration has been endorsed by Congress and by President Ronald Reagan.The topics committee is composed of nearly 20 representatives from government, industry, and academia. Thomas Maginnis, director of the National Oceanic and Atmospheric Administration's office of policy and planning, is the chairman of the topics committee.

  8. Dynamics of ocean tides

    SciTech Connect

    Maarchuk, G.I.; Kagan, B.A. )

    1989-01-01

    Ocean tide information can solve vital problems in oceanology and geophysics. Elastic properties of the Earth's crust, tidal gravity variations and deviations in trajectories of artificial satellites can be studied from the dynamics of ocean tides. This book contains mathematical models and applications on several problems related to ocean tide dynamics. The first part serves as an introduction to studies of tidal dynamics equations and the application in experimental studies. Specific problems like free oscillations and forced tidal oscillations in the oceans and the ocean-shelf system are discussed. The book deals with tidal flow in the bottom boundary layer. Data and models are presented and experimental and theoretical results are compared.

  9. Regional ocean data assimilation.

    PubMed

    Edwards, Christopher A; Moore, Andrew M; Hoteit, Ibrahim; Cornuelle, Bruce D

    2015-01-01

    This article reviews the past 15 years of developments in regional ocean data assimilation. A variety of scientific, management, and safety-related objectives motivate marine scientists to characterize many ocean environments, including coastal regions. As in weather prediction, the accurate representation of physical, chemical, and/or biological properties in the ocean is challenging. Models and observations alone provide imperfect representations of the ocean state, but together they can offer improved estimates. Variational and sequential methods are among the most widely used in regional ocean systems, and there have been exciting recent advances in ensemble and four-dimensional variational approaches. These techniques are increasingly being tested and adapted for biogeochemical applications.

  10. Comparative susceptibility among three stocks of yellow perch, Perca flavescens (Mitchill), to viral haemorrhagic septicaemia virus strain IVb from the Great Lakes

    USGS Publications Warehouse

    Olson, W.; Emmenegger, E.; Glenn, J.; Winton, J.; Goetz, F.

    2013-01-01

    The Great Lakes strain of viral haemorrhagic septicaemia virus IVb (VHSV-IVb) is capable of infecting a wide number of naive species and has been associated with large fish kills in the Midwestern United States since its discovery in 2005. The yellow perch, Perca flavescens (Mitchill), a freshwater species commonly found throughout inland waters of the United States and prized for its high value in sport and commercial fisheries, is a species documented in several fish kills affiliated with VHS. In the present study, differences in survival after infection with VHSV IVb were observed among juvenile fish from three yellow perch broodstocks that were originally derived from distinct wild populations, suggesting innate differences in susceptibility due to genetic variance. While all three stocks were susceptible upon waterborne exposure to VHS virus infection, fish derived from the Midwest (Lake Winnebago, WI) showed significantly lower cumulative % survival compared with two perch stocks derived from the East Coast (Perquimans River, NC and Choptank River, MD) of the United States. However, despite differences in apparent susceptibility, clinical signs did not vary between stocks and included moderate-to-severe haemorrhages at the pelvic and pectoral fin bases and exophthalmia. After the 28-day challenge was complete, VHS virus was analysed in subsets of whole fish that had either survived or succumbed to the infection using both plaque assay and quantitative PCR methodologies. A direct correlation was identified between the two methods, suggesting the potential for both methods to be used to detect virus in a research setting.

  11. A multi-level biological approach to evaluate impacts of a major municipal effluent in wild St. Lawrence River yellow perch (Perca flavescens).

    PubMed

    Houde, Magali; Giraudo, Maeva; Douville, Mélanie; Bougas, Bérénice; Couture, Patrice; De Silva, Amila O; Spencer, Christine; Lair, Stéphane; Verreault, Jonathan; Bernatchez, Louis; Gagnon, Christian

    2014-11-01

    The development of integrated ecotoxicological approaches is of great interest in the investigation of global concerns such as impacts of municipal wastewater effluents on aquatic ecosystems. The objective of this study was to investigate the effects of a major wastewater municipal effluent on fish using a multi-level biological approach, from gene transcription and enzyme activities to histological changes. Yellow perch (Perca flavescens) were selected based on their wide distribution, their commercial and recreational importance, and the availability of a customized microarray. Yellow perch were sampled upstream of a major municipal wastewater treatment plant (WWTP) and 4 km and 10 km downstream from its point of discharge in the St. Lawrence River (Quebec, Canada). Concentrations of perfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs) and metals/trace elements in whole body homogenates were comparable to those from other industrialized regions of the world. Genomic results indicated that the transcription level of 177 genes was significantly different (p<0.024) between exposed and non-exposed fish. Among these genes, 38 were found to be differentially transcribed at both downstream sites. Impacted genes were associated with biological processes and molecular functions such as immunity, detoxification, lipid metabolism/energy homeostasis (e.g., peroxisome proliferation), and retinol metabolism suggesting impact of WWTP on these systems. Moreover, antioxidant enzyme activities were more elevated in perch collected at the 4 km site. Biomarkers of lipid metabolism, biosynthetic activity, and aerobic capacities were significantly lower (p<0.05) in fish residing near the outfall of the effluent. Histological examination of the liver indicated no differences between sites. Correlations between PFAS, PBDE, and metal/trace element tissue concentrations and markers of peroxisomal proliferation, oxidative stress, and retinoid metabolism were found at

  12. Efficacy of exogenous hormone (GnRHa) for induced breeding of climbing perch Anabas testudineus (Bloch, 1792) and influence of operational sex ratio on spawning success.

    PubMed

    Mandal, Babita; Kumar, Rajesh; Jayasankar, P

    2016-08-01

    The climbing perch, Anabas testudineus, is an air-breathing fish having great consumer preference as a food fish and is considered a prime candidate species for aquaculture. Spawning success is an important issue while using hormones for captive induced breeding. In the first experiment, a trial was conducted to assess the efficacy of a synthetic Gonadotropin Releasing Hormone analog (sGnRHa) on the spawning success of climbing perch. Female fish were administered six different doses each with a single intramuscular injection of sGnRHa hormone at 0.002 (TOD1), 0.005 (TOD2), 0.01 (TOD3), 0.015 (TOD4), 0.02 (TOD5), 0.03 (TOD6) μg/g body weight. Similarly, males were administered half of the hormone dose of females in all the respective treatment groups. The greatest (P<0.05) relative fecundity (715.13±15.0 eggs/g female body weight) and fertilization percentage rates (93.1±8.0%) occurred when female fish were treated at the 0.015μg/g body weight dose. There was a reduction in relative fecundity and hatching rate in female fish injected with the largest dose (1.5μL/g body weight) of sGnRHa. A second experiment was conducted to assess the effect of a different male-female ratio on optimum spawning success in climbing perch. For this study a different female to male ratio (1:1, 1:2, 1:3 and 1:4) and male to female ratio (1:1, 1:2 and 1:3) were used. There were a greater (P<0.05) relative fecundity (886.62±17.9 eggs/g female body weight), fertilization (98±6.7%) and hatching (99±5.4%) rates with the female to male ratio of 1:2. This indicated that the hormone dose of 0.015μg/g body weight and a female-male ratio of 1:2 are optimal for enhanced spawning success in the climbing perch. PMID:27346586

  13. Efficacy of exogenous hormone (GnRHa) for induced breeding of climbing perch Anabas testudineus (Bloch, 1792) and influence of operational sex ratio on spawning success.

    PubMed

    Mandal, Babita; Kumar, Rajesh; Jayasankar, P

    2016-08-01

    The climbing perch, Anabas testudineus, is an air-breathing fish having great consumer preference as a food fish and is considered a prime candidate species for aquaculture. Spawning success is an important issue while using hormones for captive induced breeding. In the first experiment, a trial was conducted to assess the efficacy of a synthetic Gonadotropin Releasing Hormone analog (sGnRHa) on the spawning success of climbing perch. Female fish were administered six different doses each with a single intramuscular injection of sGnRHa hormone at 0.002 (TOD1), 0.005 (TOD2), 0.01 (TOD3), 0.015 (TOD4), 0.02 (TOD5), 0.03 (TOD6) μg/g body weight. Similarly, males were administered half of the hormone dose of females in all the respective treatment groups. The greatest (P<0.05) relative fecundity (715.13±15.0 eggs/g female body weight) and fertilization percentage rates (93.1±8.0%) occurred when female fish were treated at the 0.015μg/g body weight dose. There was a reduction in relative fecundity and hatching rate in female fish injected with the largest dose (1.5μL/g body weight) of sGnRHa. A second experiment was conducted to assess the effect of a different male-female ratio on optimum spawning success in climbing perch. For this study a different female to male ratio (1:1, 1:2, 1:3 and 1:4) and male to female ratio (1:1, 1:2 and 1:3) were used. There were a greater (P<0.05) relative fecundity (886.62±17.9 eggs/g female body weight), fertilization (98±6.7%) and hatching (99±5.4%) rates with the female to male ratio of 1:2. This indicated that the hormone dose of 0.015μg/g body weight and a female-male ratio of 1:2 are optimal for enhanced spawning success in the climbing perch.

  14. An update of hydrologic conditions and distribution of selected constituents in water, Snake River Plain aquifer and perched groundwater zones, Idaho National Laboratory, Idaho, emphasis 2006-08

    USGS Publications Warehouse

    Davis, Linda C.

    2010-01-01

    Since 1952, radiochemical and chemical wastewater discharged to infiltration ponds (also called percolation ponds), evaporation ponds, and disposal wells at the Idaho National Laboratory (INL) has affected water quality in the eastern Snake River Plain aquifer and perched groundwater zones underlying the INL. The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, maintains groundwater monitoring networks at the INL to determine hydrologic trends, and to delineate the movement of radiochemical and chemical wastes in the aquifer and in perched groundwater zones. This report presents an analysis of water-level and water-quality data collected from aquifer and perched groundwater wells in the USGS groundwater monitoring networks during 2006-08. Water in the Snake River Plain aquifer primarily moves through fractures and interflow zones in basalt, generally flows southwestward, and eventually discharges at springs along the Snake River. The aquifer primarily is recharged from infiltration of irrigation water, infiltration of streamflow, groundwater inflow from adjoining mountain drainage basins, and infiltration of precipitation. From March-May 2005 to March-May 2008, water levels in wells generally remained constant or rose slightly in the southwestern corner of the INL. Water levels declined in the central and northern parts of the INL. The declines ranged from about 1 to 3 feet in the central part of the INL, to as much as 9 feet in the northern part of the INL. Water levels in perched groundwater wells around the Advanced Test Reactor Complex (ATRC) also declined. Detectable concentrations of radiochemical constituents in water samples from wells in the Snake River Plain aquifer at the INL generally decreased or remained constant during 2006-08. Decreases in concentrations were attributed to decreased rates of radioactive-waste disposal, radioactive decay, changes in waste-disposal methods, and dilution from recharge and underflow. In April

  15. Characterization and evaluation of sex-specific expression of suppressors of cytokine signaling (SOCS)-1 and -3 in juvenile yellow perch (Perca flavescens) treated with lipopolysaccharide.

    PubMed

    Shepherd, Brian S; Rees, Christopher B; Binkowski, Fred P; Goetz, Frederick W

    2012-09-01

    The suppressor of cytokine signaling (SOCS) proteins are a family of intracellular proteins that are centrally involved with vertebrate growth, development and immunity via their effects as negative feed-back regulators of cytokine (and hormone) signaling. The genes for SOCS-1 & -3 were cloned, sequences analyzed and expression patterns examined in the commercially-important teleost, yellow perch (Perca flavescens). The deduced (mature) proteins for yellow perch (yp)SOCS-1 and (yp)SOCS-3 consist of 211 and 205 amino acids, respectively. Functional domains such as the Src homology-2 (SH2) and SOCS-box were present in ypSOCS-1 and ypSOCS-3 and these domains were well conserved between teleost species. Sequence analysis showed that ypSOCS-1 & -3 share highest homology (among similar teleost sequences), to the stickleback (Gasterosteus aculatus) SOCS-1 & -3 protein homologs. To investigate sex-specific expression of the ypSOCS-1 and ypSOCS-3 mRNAs, juvenile male and female yellow perch were immunologically challenged with a single injection (10 μg/g bw) of lipopolysaccharide (LPS) and tissues (gill, head kidney, kidney, liver and spleen) were sampled over a 48-h time-course. Quantitative real-time PCR analysis showed that ypSOCS-1 & -3 were expressed in all tissues examined and at all sampling time-points. LPS injection significantly induced ypSOCS-1 & -3 mRNA levels in gill, head kidney, liver, kidney and spleen, with maximal induction occurring at 6 h post-injection in each tissue. By 48-h post-injection, expression levels for ypSOCS-1 & -3 mRNAs approached, or reached, control levels in all tissues examined. While there were statistical interactions among variables (treatment, time and sex) for ypSOCS-1, we only found a main effect of sex on SOCS-3 mRNA expression in head kidney with higher copy numbers occurring in males than in females treated with LPS. Sexually-dimorphic expression of SOCS-1 or -3 mRNA has not been examined, or described, in a teleost. Our

  16. 78 FR 32556 - Safety Zone; 2013 Ocean City Air Show, Atlantic Ocean; Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2013 Ocean City Air Show, Atlantic Ocean... establishing a temporary safety zone on the navigable waters of the Atlantic Ocean in the vicinity of Ocean... Atlantic Ocean in Ocean City, MD. In recent years, there have been unfortunate instances of jets and...

  17. 76 FR 31235 - Safety Zone; Ocean City Air Show, Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Ocean City Air Show, Atlantic Ocean, Ocean... establish a temporary safety zone on the Atlantic Ocean in the vicinity of Ocean City, MD to support the... Atlantic Ocean to protect mariners from the hazards associated with air show events. DATES: This rule...

  18. Thermodynamic Equations of State for Aqueous Solutions Applied to Deep Icy Satellite and Exoplanet Oceans

    NASA Astrophysics Data System (ADS)

    Vance, S.; Brown, J. M.; Bollengier, O.; Journaux, B.; Sotin, C.; Choukroun, M.; Barnes, R.

    2014-12-01

    Supporting life in icy world or exoplanet oceans may require global seafloor chemical reactions between water and rock. Such interactions have been regarded as limited in larger icy worlds such as Ganymede and Titan, where ocean depths approach 800 km and GPa pressures (>10katm). If the oceans are composed of pure water, such conditions are consistent with the presence of dense ice phases V and VI that cover the rocky seafloor. Exoplanets with oceans can obtain pressures sufficient to generate ices VII and VIII. We have previously demonstrated temperature gradients in such oceans on the order of 20 K or more, resulting from fluid compressibility in a deep adiabatic ocean based on our experimental work. Accounting for increases in density for highly saline oceans leads to the possibility of oceans perched under and between high pressure ices. Ammonia has the opposite effect, instead decreasing ocean density, as reported by others and confirmed by our laboratory measurements in the ammonia water system. Here we report on the completed equation of state for aqueous ammonia derived from our prior measurements and optimized global b-spline fitting methods We use recent diamond anvil cell measurements for water and ammonia to extend the equation of state to 400°C and beyond 2 GPa, temperatures and pressures applicable to icy worlds and exoplanets. Densities show much less temperature dependence but comparabe high-pressure derivatives to previously published ammonia-water properties derived for application to Titan (Croft et al. 1988). Thermal expansion is in better agreement with the more self-consistent equation of state of Tillner-Roth and Friend (1998). We also describe development of a planetary NaCl equation of state using recent measurements of phase boundaries and sound speeds. We examine implications of realistic ocean-ice thermodynamics for Titan and exoplanet interiors using the methodology recently applied to Ganymede for oceans dominated by MgSO4. High

  19. Southern Ocean cephalopods.

    PubMed

    Collins, Martin A; Rodhouse, Paul G K

    2006-01-01

    The Southern Ocean cephalopod fauna is distinctive, with high levels of endemism in the squid and particularly in the octopodids. Loliginid squid, sepiids and sepiolids are absent from the Southern Ocean, and all the squid are oceanic pelagic species. The octopodids dominate the neritic cephalopod fauna, with high levels of diversity, probably associated with niche separation. In common with temperate cephalopods, Southern Ocean species appear to be semelparous, but growth rates are probably lower and longevity greater than temperate counterparts. Compared with equivalent temperate species, eggs are generally large and fecundity low, with putative long development times. Reproduction may be seasonal in the squid but is extended in the octopodids. Cephalopods play an important role in the ecology of the Southern Ocean, linking the abundant mesopelagic fish and crustaceans with higher predators such as albatross, seals and whales. To date Southern Ocean cephalopods have not been commercially exploited, but there is potential for exploitation of muscular species of the Family Ommastrephidae.

  20. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography. PMID:26723303

  1. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography.

  2. Global Ocean Phytoplankton

    NASA Technical Reports Server (NTRS)

    Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

    2013-01-01

    Phytoplankton are free-floating algae that grow in the euphotic zone of the upper ocean, converting carbon dioxide, sunlight, and available nutrients into organic carbon through photosynthesis. Despite their microscopic size, these photoautotrophs are responsible for roughly half the net primary production on Earth (NPP; gross primary production minus respiration), fixing atmospheric CO2 into food that fuels our global ocean ecosystems. Phytoplankton thus play a critical role in the global carbon cycle, and their growth patterns are highly sensitive to environmental changes such as increased ocean temperatures that stratify the water column and prohibit the transfer of cold, nutrient richwaters to the upper ocean euphotic zone.

  3. World Ocean Circulation Experiment

    NASA Technical Reports Server (NTRS)

    Clarke, R. Allyn

    1992-01-01

    The oceans are an equal partner with the atmosphere in the global climate system. The World Ocean Circulation Experiment is presently being implemented to improve ocean models that are useful for climate prediction both by encouraging more model development but more importantly by providing quality data sets that can be used to force or to validate such models. WOCE is the first oceanographic experiment that plans to generate and to use multiparameter global ocean data sets. In order for WOCE to succeed, oceanographers must establish and learn to use more effective methods of assembling, quality controlling, manipulating and distributing oceanographic data.

  4. Do Carolina chickadees (Poecile carolinensis) and tufted titmice (Baeolophus bicolor) attend to the head or body orientation of a perched avian predator?

    PubMed

    Kyle, Steven C; Freeberg, Todd M

    2016-05-01

    Individuals of many prey species adjust their foraging behavior in response to the presence of a predator. Responding to predators takes time away from searching for and exploiting food resources. To balance between the need to avoid predation and the need to forage, individuals should attend to cues from predators that indicate risk. Two such cues might be the predator's head orientation (where it might be looking) and body orientation (where it might be moving). In the current study, flocks of Carolina chickadees, Poecile carolinensis, and tufted titmice, Baeolophus bicolor, were presented with perched hawk and owl models. Predator model head and body orientation were independently manipulated relative to a feeding station birds were using. Chickadees and titmice avoided the feeders more when the heads of the models were facing toward the feeders compared to facing away from the feeders. Calling behavior of birds was also affected by head orientation of the models. No effect of predator body orientation on chickadee and titmouse behavior was detected. The results indicate that when chickadees and titmice detect a perched avian predator, they assess risk primarily based upon its head orientation. (PsycINFO Database Record

  5. Polychlorinated biphenyls in adult black bass and yellow perch were not associated with their reproductive success in the upper Hudson River, New York, USA.

    PubMed

    Maceina, Michael J; Sammons, Steven M

    2013-07-01

    Although production and use of polychlorinated biphenyls (PCBs) ceased nearly 35 yr ago, questions still remain concerning the potential chronic effects these compounds may have on wild fish, including their reproductive success. In the upper Hudson River, New York, USA, fish were exposed to PCBs primarily from 2 manufacturing plants located approximately 320 km upstream of New York City, New York, from the 1940s to 1977. The authors collected yellow perch (Perca flavescens), smallmouth bass (Micropterus dolomieu), and largemouth bass (M. salmoides) using electrofishing, measured PCBs in these adults, and estimated abundance and size of their offspring at age 1 yr (age-1 fish). Fish were collected annually from 2004 to 2009 from 1 control site upstream of the PCB discharge sites and from 2 sites downstream from where PCBs were released. These sites (pools) are separated by a series of dams, locks, and canals. Muscle tissue wet weight PCB and lipid-based PCB concentrations in adults in the 2 PCB exposure pools averaged approximately 1 to 3 µg/g and 100 to 500 µg/g, respectively. Age-1 abundances were not related to adult PCB concentrations but were inversely related to river flow. Size of age-1 fish was slightly greater at the PCB-exposure sites. Levels of PCBs in yellow perch, largemouth bass, and smallmouth bass in the upper Hudson River did not impair or reduce recruitment or reproductive success. PMID:23440915

  6. Polychlorinated biphenyls in adult black bass and yellow perch were not associated with their reproductive success in the upper Hudson River, New York, USA.

    PubMed

    Maceina, Michael J; Sammons, Steven M

    2013-07-01

    Although production and use of polychlorinated biphenyls (PCBs) ceased nearly 35 yr ago, questions still remain concerning the potential chronic effects these compounds may have on wild fish, including their reproductive success. In the upper Hudson River, New York, USA, fish were exposed to PCBs primarily from 2 manufacturing plants located approximately 320 km upstream of New York City, New York, from the 1940s to 1977. The authors collected yellow perch (Perca flavescens), smallmouth bass (Micropterus dolomieu), and largemouth bass (M. salmoides) using electrofishing, measured PCBs in these adults, and estimated abundance and size of their offspring at age 1 yr (age-1 fish). Fish were collected annually from 2004 to 2009 from 1 control site upstream of the PCB discharge sites and from 2 sites downstream from where PCBs were released. These sites (pools) are separated by a series of dams, locks, and canals. Muscle tissue wet weight PCB and lipid-based PCB concentrations in adults in the 2 PCB exposure pools averaged approximately 1 to 3 µg/g and 100 to 500 µg/g, respectively. Age-1 abundances were not related to adult PCB concentrations but were inversely related to river flow. Size of age-1 fish was slightly greater at the PCB-exposure sites. Levels of PCBs in yellow perch, largemouth bass, and smallmouth bass in the upper Hudson River did not impair or reduce recruitment or reproductive success.

  7. The effects of a perch, dust bath, and nest box, either alone or in combination as used in furnished cages, on the welfare of laying hens.

    PubMed

    Barnett, J L; Tauson, R; Downing, J A; Janardhana, V; Lowenthal, J W; Butler, K L; Cronin, G M

    2009-03-01

    This experiment examined the welfare-related effects of individual furniture items alone or in combination in a factorial experiment using Hy-Line Brown hens housed in 8-bird furnished cages. Welfare was assessed during two 8-wk sampling periods commencing at 29 and 59 wk of age. Measurement of stress, immunology, feather, foot and claw condition, and behavior were taken, and bone strength was measured at the end of the experiment. With the exception of the positive effects of a perch on bone strength, any effects of furniture items were relatively small, even though the furniture was extensively used. Although there were changes in behavior and small changes in feather, foot, and claw condition, it is unclear whether these changes have any meaningful implications for welfare. In this experiment there were 2 additional external control treatments for a small study that examined the effects of increasing space per bird (8 birds in single- and double-width cages) and the effects of group size (8 and 16 birds in double-width cages); using similar methodologies, these treatments showed differences in egg corticosterone concentrations and evidence of immunosuppression. Together, these data suggest that although furniture when present was well-used, any effects of furniture on hen welfare measured by physical and physiological traits, other than the benefit of a perch on bone strength, were smaller than effects of group size and space allowance. PMID:19211513

  8. Benefits of Turbid River Plume Habitat for Lake Erie Yellow Perch (Perca flavescens) Recruitment Determined by Juvenile to Larval Genotype Assignment

    PubMed Central

    Carreon-Martinez, Lucia B.; Walter, Ryan P.; Johnson, Timothy B.; Ludsin, Stuart A.; Heath, Daniel D.

    2015-01-01

    Nutrient-rich, turbid river plumes that are common to large lakes and coastal marine ecosystems have been hypothesized to benefit survival of fish during early life stages by increasing food availability and (or) reducing vulnerability to visual predators. However, evidence that river plumes truly benefit the recruitment process remains meager for both freshwater and marine fishes. Here, we use genotype assignment between juvenile and larval yellow perch (Perca flavescens) from western Lake Erie to estimate and compare recruitment to the age-0 juvenile stage for larvae residing inside the highly turbid, south-shore Maumee River plume versus those occupying the less turbid, more northerly Detroit River plume. Bayesian genotype assignment of a mixed assemblage of juvenile (age-0) yellow perch to putative larval source populations established that recruitment of larvae was higher from the turbid Maumee River plume than for the less turbid Detroit River plume during 2006 and 2007, but not in 2008. Our findings add to the growing evidence that turbid river plumes can indeed enhance survival of fish larvae to recruited life stages, and also demonstrate how novel population genetic analyses of early life stages can contribute to determining critical early life stage processes in the fish recruitment process. PMID:25954968

  9. Expression kinetics of key genes in the early innate immune response to Great Lakes viral hemorrhagic septicemia virus IVb infection in yellow perch (Perca flavescens)

    USGS Publications Warehouse

    Olson, Wendy; Emmenegger, Eveline; Glenn, Jolene; Simchick, Crystal; Winton, Jim; Goetz, Frederick

    2013-01-01

    The recently discovered strain of viral hemorrhagic septicemia virus, VHSV-IVb, represents an example of the introduction of an extremely pathogenic rhabdovirus capable of infecting a wide variety of new fish species in a new host-environment. The goal of the present study was to delineate the expression kinetics of key genes in the innate immune response relative to the very early stages of VHSV-IVb infection using the yellow perch (Perca flavescens) as a model. Administration of VHSV-IVb by IP-injection into juvenile yellow perch resulted in 84% cumulative mortality, indicating their high susceptibility to this disease. In fish sampled in the very early stages of infection, a significant up-regulation of Mx gene expression in the liver, as well as IL-1β and SAA activation in the head kidney, spleen, and liver was directly correlated to viral load. The potential down-regulation of Mx in the hematopoietic tissues, head kidney and spleen, may represent a strategy utilized by the virus to increase replication.

  10. [Metazoan parasites of roach Rutilus rutilus (L., 1758), bream Abramis brama (L., 1758) and perch Perca fluviatilis L., 1758 from lakes of river Łyna watershed].

    PubMed

    Kuształa, Marzena

    2010-01-01

    During the years 2004-2006 the parasitological autopsies of three species of fish: roach Rutilus rutilus (L.), bream Abramis brama (L.) and perch Perca fluviatilis L. from three lakes situated in warmińsko-mazurskie voivodeship were done. The aim of this study was comparable analysis of Metazoan parasite communities which occur in roach, bream and perch in three lakes of river Łyna watershed. These lakes differ by physical (size, depth, eutrophication degree) and biological factors (composition of free-living organisms). The studies showed some relationships between size of fishes and the frequency of some parasite species as well as some relationships in seasonal dynamic of occurrence and maturation of ecto- and endoparasites, which were connected with temperature--main factor regulating processes of fish colonization by parasites and future development of parasites. In quantitative and qualitative analysis of fish parasite community structure the following indexes were used: species richness (S), species diversity of Shannon-Weaver (H'), species diversity of Brillouin (HB) and index of domination Berger-Parker (D). Studies showed that the main indexes of communities structure which indicating on occurring differences between lakes were indexes of diversity component communities and infracommunities and also index of dominance. Communities of monogeneans (roaches and breams) can be use as indicators of water environment. Apart from communities of gills parasites also alfamesotrophic lake Łańskie and eutrophic Mielno lake were differenced by eyes parasites and allogenic community of bream parasites and by intestinal parasites of roach.

  11. Do Carolina chickadees (Poecile carolinensis) and tufted titmice (Baeolophus bicolor) attend to the head or body orientation of a perched avian predator?

    PubMed

    Kyle, Steven C; Freeberg, Todd M

    2016-05-01

    Individuals of many prey species adjust their foraging behavior in response to the presence of a predator. Responding to predators takes time away from searching for and exploiting food resources. To balance between the need to avoid predation and the need to forage, individuals should attend to cues from predators that indicate risk. Two such cues might be the predator's head orientation (where it might be looking) and body orientation (where it might be moving). In the current study, flocks of Carolina chickadees, Poecile carolinensis, and tufted titmice, Baeolophus bicolor, were presented with perched hawk and owl models. Predator model head and body orientation were independently manipulated relative to a feeding station birds were using. Chickadees and titmice avoided the feeders more when the heads of the models were facing toward the feeders compared to facing away from the feeders. Calling behavior of birds was also affected by head orientation of the models. No effect of predator body orientation on chickadee and titmouse behavior was detected. The results indicate that when chickadees and titmice detect a perched avian predator, they assess risk primarily based upon its head orientation. (PsycINFO Database Record PMID:27195595

  12. Ocean engineering for ocean thermal energy conversion

    SciTech Connect

    Not Available

    1982-01-01

    The panel on OTEC Ocean Engineering of the National Research Council was formed to assess the state of ocean engineering knowledge, technology, and practice necessary to design, construct, and operate OTEC plants. The panel concentrated its study on platforms, moorings, and foundations; the cold water pipe; and submarine cables for electric power transmission. The panel did not address the design and engineering of power plants; institutional and management issues or the commercial feasibility of OTEC; or its environmental impacts. The panel focused instead on determining the state of development of several of the ocean engineering technologies needed to design and construct a 40-MWe OTEC plant; it also examined the technical feasibility and advantages of larger and smaller plants.

  13. Blue ocean strategy.

    PubMed

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades. PMID:15559577

  14. Blue ocean strategy.

    PubMed

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  15. Ocean thermal energy conversion

    SciTech Connect

    Avery, W.H.

    1983-03-17

    A brief explanation of the Ocean Thermal Energy Conversion (OTEC) concept and an estimate of the amount of energy that can be produced from the ocean resource without introducing environmental concerns are presented. Use of the OTEC system to generate electric power and products which can replace fossil fuels is shown. The OTEC program status and its prospects for the future are discussed.

  16. The Living Ocean.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    This teaching guide contains information, activities, and discussion questions and answers about oceans for grades nine and ten. The information section covers the following topics: studying global ocean color from space, what can be seen from space, phytoplankton, carbon dioxide, and the greenhouse effect of the earth. (MKR)

  17. Blue Ocean Thinking

    ERIC Educational Resources Information Center

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  18. Communicating Ocean Acidification

    ERIC Educational Resources Information Center

    Pope, Aaron; Selna, Elizabeth

    2013-01-01

    Participation in a study circle through the National Network of Ocean and Climate Change Interpretation (NNOCCI) project enabled staff at the California Academy of Sciences to effectively engage visitors on climate change and ocean acidification topics. Strategic framing tactics were used as staff revised the scripted Coral Reef Dive program,…

  19. An Ocean Mural.

    ERIC Educational Resources Information Center

    Graham, Frank; Graham, Ada

    1998-01-01

    Introduces a class project on oceans, fishes, and fishing industries around the world. Groups of students make a mural of the world, filling the oceans with accurate drawings of fish, fishing boats, and fishing equipment. Students learn about the importance of fish in various cultures and about the migration routes of fish. Includes a resource…

  20. A Nation of Oceans.

    ERIC Educational Resources Information Center

    Weber, Michael; Tinney, Richard

    This book is for people that want to know more about the oceans, its inhabitants, and the ocean processes. The main text of the book describes individual marine ecosystems including offshore open water, benthic, nearshore tropical, nearshore temperate, and nearshore arctic ecosystems. Discussed are some of the basic ecological principles found…

  1. Global Ocean Phytoplankton

    NASA Technical Reports Server (NTRS)

    Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

    2014-01-01

    Marine phytoplankton are responsible for roughly half the net primary production (NPP) on Earth, fixing atmospheric CO2 into food that fuels global ocean ecosystems and drives the ocean's biogeochemical cycles. Phytoplankton growth is highly sensitive to variations in ocean physical properties, such as upper ocean stratification and light availability within this mixed layer. Satellite ocean color sensors, such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; McClain 2009) and Moderate Resolution Imaging Spectroradiometer (MODIS; Esaias 1998), provide observations of sufficient frequency and geographic coverage to globally monitor physically-driven changes in phytoplankton distributions. In practice, ocean color sensors retrieve the spectral distribution of visible solar radiation reflected upward from beneath the ocean surface, which can then be related to changes in the photosynthetic phytoplankton pigment, chlorophyll- a (Chla; measured in mg m-3). Here, global Chla data for 2013 are evaluated within the context of the 16-year continuous record provided through the combined observations of SeaWiFS (1997-2010) and MODIS on Aqua (MODISA; 2002-present). Ocean color measurements from the recently launched Visible and Infrared Imaging Radiometer Suite (VIIRS; 2011-present) are also considered, but results suggest that the temporal calibration of the VIIRS sensor is not yet sufficiently stable for quantitative global change studies. All MODISA (version 2013.1), SeaWiFS (version 2010.0), and VIIRS (version 2013.1) data presented here were produced by NASA using consistent Chla algorithms.

  2. Ocean-atmospheric linkages

    NASA Technical Reports Server (NTRS)

    Rintoul, Stephen R.

    1992-01-01

    This chapter focuses on the role of the ocean in the global carbon cycle on the time scale of decades to centuries. The input rate of CO2 to the atmosphere due to fossil fuel burning and deforestation has continued to increase over the last century. To balance the global carbon budget, a sink is required whose magnitude is changing on similar time scales. We have sought to identify aspects of the ocean system that are capable of responding on decadal time scales, to examine our present ability to model such changes, and to pinpoint ways in which this ability could be improved. Many other important aspects of the ocean's role in global change are not addressed, including the importance of oceanic heat transport and thermal inertia to the climate system, biogeochemical cycling of elements other than carbon, and the importance of the ocean as a source or sink of trace gases.

  3. Oceanic emissions of ammonia

    NASA Astrophysics Data System (ADS)

    Paulot, F.; Jacob, D. J.; Johnson, M.; Bell, T. G.; Stock, C. A.; Doney, S. C.

    2013-12-01

    Half of natural ammonia (NH3) emissions is thought to originate from the oceans. Such large emissions have implications for the global budget of N and the acidity of marine aerosols. We develop two new inventories of oceanic NH3 emissions based on simulated monthly NH3 seawater concentrations from the GFDL-COBALT and the CESM-BEC ocean models. These new inventories explicitly account for the effect of temperature on the water-atmosphere exchange of NH3. We evaluate these inventory using cruise observations of gas-phase ammonia (AMT cruises) and ammonium (NOAA cruises) as well as seawater measurement of NHx. Implications of atmospheric NHx observations for the exchange of N between ocean and land and ocean N/P limitations are discussed.

  4. Mesoscale ocean dynamics modeling

    SciTech Connect

    mHolm, D.; Alber, M.; Bayly, B.; Camassa, R.; Choi, W.; Cockburn, B.; Jones, D.; Lifschitz, A.; Margolin, L.; Marsden, L.; Nadiga, B.; Poje, A.; Smolarkiewicz, P.; Levermore, D.

    1996-05-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The ocean is a very complex nonlinear system that exhibits turbulence on essentially all scales, multiple equilibria, and significant intrinsic variability. Modeling the ocean`s dynamics at mesoscales is of fundamental importance for long-time-scale climate predictions. A major goal of this project has been to coordinate, strengthen, and focus the efforts of applied mathematicians, computer scientists, computational physicists and engineers (at LANL and a consortium of Universities) in a joint effort addressing the issues in mesoscale ocean dynamics. The project combines expertise in the core competencies of high performance computing and theory of complex systems in a new way that has great potential for improving ocean models now running on the Connection Machines CM-200 and CM-5 and on the Cray T3D.

  5. Ocean acidification postcards

    USGS Publications Warehouse

    Schreppel, Heather A.; Cimitile, Matthew J.

    2011-01-01

    The U.S. Geological Survey (USGS) is conducting research on ocean acidification in polar, temperate, subtropical, and tropical regions including the Arctic, West Florida Shelf, and the Caribbean. Project activities include field assessment, experimental laboratory studies, and evaluation of existing data. The USGS is participating in international and interagency working groups to develop research strategies to increase understanding of the global implications of ocean acidification. Research strategies include new approaches for seawater chemistry observation and modeling, assessment of physiological effects on organisms, changes in marine ecosystem structure, new technologies, and information resources. These postcards highlight ongoing USGS research efforts in ocean acidification and carbon cycling in marine and coastal ecosystems in three different regions: polar, temperate, and tropical. To learn more about ocean acidification visit: http://coastal.er.usgs.gov/ocean-acidification/.

  6. Ocean General Circulation Models

    SciTech Connect

    Yoon, Jin-Ho; Ma, Po-Lun

    2012-09-30

    1. Definition of Subject The purpose of this text is to provide an introduction to aspects of oceanic general circulation models (OGCMs), an important component of Climate System or Earth System Model (ESM). The role of the ocean in ESMs is described in Chapter XX (EDITOR: PLEASE FIND THE COUPLED CLIMATE or EARTH SYSTEM MODELING CHAPTERS). The emerging need for understanding the Earth’s climate system and especially projecting its future evolution has encouraged scientists to explore the dynamical, physical, and biogeochemical processes in the ocean. Understanding the role of these processes in the climate system is an interesting and challenging scientific subject. For example, a research question how much extra heat or CO2 generated by anthropogenic activities can be stored in the deep ocean is not only scientifically interesting but also important in projecting future climate of the earth. Thus, OGCMs have been developed and applied to investigate the various oceanic processes and their role in the climate system.

  7. 75 FR 18778 - Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Ocean City Air Show 2010, Atlantic Ocean... proposes establishing a temporary safety zone on the Atlantic Ocean in the vicinity of Ocean City, Maryland... the Atlantic Ocean to protect mariners and the public from the hazards associated with air show...

  8. Molecular Characterization and Sex-Specific Tissue Expression of Estrogen Receptor Alpha (esr1), Estrogen Receptor Beta-a (esr2a) and Ovarian Aromatase (cyp19a1a) in Yellow Perch (Perca flavescens)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow perch (Perca flavescens) exhibit an estrogen-stimulated sexual size dimorphism (SSD) wherein females grow faster and larger than males. To aid in the examination of this phenomenon, the cDNA sequences encoding estrogen receptor-alpha (esr1), estrogen receptor-beta-a (esr2a) and ovarian aroma...

  9. Annual Developmental Cycle of Gonads of European Perch Females (Perca fluviatilis L.) from Natural Sites and a Canal Carrying Post-cooling Water from the Dolna Odra Power Plant (NW Poland).

    PubMed

    Kirczuk, Lucyna; Domagała, Józef; Pilecka-Rapacz, Małgorzata

    2015-01-01

    The European perch is a species endowed with high adaptation capabilities as regards different environmental conditions. The aim of the study was to analyse the annual developmental cycle of ovaries of the European perch from the Oder river, Lake Dąbie and a drainage canal (Warm Canal) carrying post-cooling water from the Dolna Odra power plant (annual average water temperature in the canal is higher by 6-8°C than the water of the other sampling sites). Most of the female perch caught in the canal carrying post-cooling water had immature stage 2 gonads (delayed development of the gonads) and were smaller than the fish from the other sites. No traces of spawning in the form of deposed egg strings were found in the drainage canal. Adult individuals avoid high temperatures found in the Warm Canal. In April, in perch from all sites, ovaries with post-spawning oocytes were observed. The spawning season of the females lasted from the beginning of April until May. Stage 4 of gonad development, with oocytes in advanced vitellogenesis, was the longest and ranged from September through February.

  10. The Messinian Salinity Crisis: what can we expect from drilling the perched basins from the Balearic Promontory?

    NASA Astrophysics Data System (ADS)

    Johanna, Lofi; Angelo, Camerlenghi; Agnès, Maillard; Diana, Ochoa

    2015-04-01

    In spite of 40 years of multi-disciplinary research conducted on the Messinian Salinity Crisis (MSC) event, modalities, timing, causes, chronology and consequence at local and planetary scale of this event are still not yet fully understood, and the MSC event remains one of the longest-living controversies in Earth Science. A key factor for the controversy is certainly the lack of a complete record of the MSC deposits preserved in the deepest Mediterranean basins. Anywhere else, on the continental shelves and slopes, the MSC mostly generated a sedimentary/time lag corresponding to a widespread erosional surface. Correlations with the depositional units locally preserved onshore are thus complex, preventing the construction of a coherent scenario linking the outcropping MSC evaporites, the erosion on the margins, and the deposition of clastics and evaporites in the abyssal plains. Recent works based on seismic profile interpretations and conducted on the Balearic promontory allowed to evidence a series of small perched basins presently lying in different water depths stepped from the coast line down to the deep basin. These topographic lows trapped sedimentary series up to 500m thick, interpreted as MSC in age (Maillard et al., 2014; Mocnik et al., 2014; Driussi et al., in press). In the most proximal basins, these deposits have been drilled and logged for industriel purposes and consist of gypsum beds interbedded with marls. Ochoa et al. (submitted) demonstrated that these MSC deposits correlate with the Primary Lower Gypsum sequence deposited in marginal settings before the drawdown phase (Lugli et al., 2010) and that are now observed onshore in tectonically active areas. The basins located in more distal locations also contain MSC deposits (including <200m thick salt layers) but these have not been drilled. The relative age and chronology of the MSC deposits from one basin to another thus still need to be defined. The Balearic Promontory is probably the only

  11. Temporal and spatial variability of Fe and Mn in perched groundwater flowing through weathered argillite underlying a steep forested hillslope

    NASA Astrophysics Data System (ADS)

    Kim, H.; Bishop, J. K.

    2013-12-01

    Groundwater flowing through weathered bedrock dictates the runoff chemistry to streams in many catchments yet; its chemical evolution has been rarely documented. In particular, observations of Fe and Mn dynamics in groundwater are extremely challenging due to their high reactivity. To preserve the sample integrity for these elements we have developed a new sampling scheme that is applicable to autosamplers; a gravitational filtration system (GFS). GFS is capable of filtering samples by gravity within 30 minutes after the sampling. The GFS samples showed a good agreement with reference samples, which were collected following the standard sampling method for trace metals (i.e. immediate filtration and acidification). Since October 2011, GFS has been employed to monitor Fe and Mn in perched groundwater that moves through weathered argillite in an intensively instrumented hillslope (Rivendell), in the Angelo Coast Range Reserve. The study site is located at the headwaters of the Eel River, northern California, characterized by a typical coastal Californian Mediterranean climate. We collected groundwater samples at 3 wells along the hillslope (upslope (W10), mid-slope (W3) and near the creek (W1)) with 1-3 day intervals. Additionally, rainwater and throughfall samples were collected at a meadow near the hillslope and at the middle of the hillslope, respectively. The results from our observations indicate that Fe and Mn exhibit distinct spatial and temporal behavior under variable hydrologic conditions. The concentrations of Fe in throughfall vs. rainwater were similar (0.45μM vs. 0.49μM), but Mn in throughfall was 10-fold higher than that in rainwater (1.2 μM vs. 0.1 μM). In the early rainy season, W10's water table was deep (-18m) and Fe and Mn in W10 were 30-150 nM and 1-2 μM, respectively. As the rainy season proceeds, W10's water table rose by 4-6m, indicating the arrival of new water. At this time, Mn in W10 decreased to ~0.1 μM, synchronizing with the water

  12. Hydrogeochemical, Stable Isotopes and Hydrology of Fogo Volcano Perched Aquifers: São Miguel Island, Azores (Portugal)

    NASA Astrophysics Data System (ADS)

    Antunes, P. C.; Boutt, D. F.; Martini, A. M.; Ferstad, J.; Rodrigues, F. C.

    2012-12-01

    Fogo Volcano is located at central part of São Miguel Island and corresponds to a polygenetic volcano with a caldera made by an intercalated accumulation of volcaniclastic deposits and lava flows. São Miguel Island is one of the nine volcanic islands that form the Azores Archipelago. The volcano is 950 meters high, with a caldera diameter of 3.2 Km, which holds a lake inside. The last eruption occurred in 1563-1564, as one of a group of seven traquitic eruptions occurring within the last 5000 years. The volcanic activity is related to hydrothermal activity in a geothermal field located in the volcanoes North flank. The hydrology of Fogo Volcano is characterized by a series of perched-water bodies drained by a large number of springs grouped at different altitudes on the volcano flanks. It is possible to identify three types of water (1) Fresh water, cold temperature (12 - 17 C) with low dissolved solids contents (average conductivity of 179 μS/cm), pH range between 6.60 and 7.82, dominated by the major ions Na, K, HCO3, and Cl, and correspond mainly to sodium bicarbonate type water. (2) Mineral water, cold temperature (12.5 - 19.4 C) with low dissolved solids contents (average conductivity of 261 μS/cm), acid pH range between 4.62 and 6.79, and correspond mainly to sodium bicarbonate type water. (3) Thermal water, with temperature of 32 C, high dissolved solids content (4.62 mS/cm), with a pH around 4.50 and belongs to sodium sulfate type water. South Fogo volcano have only fresh water springs and at high elevation, springs drained from pumice fall deposits near 700 m of altitude. Water dissolved solids contents increased slightly with springs at lower altitude due to water-rock interaction. Springs sampled around 700 m high have a conductivity average of 85 μS/cm, at 520 m an average of 129 μS/cm, at 430 m an average of 182 μS/cm, at 200 m an average of 192 μS/cm and at 12 m high sea level and average of 472 μS/cm. This trend is observed at North Fogo

  13. Ocean energy program summary

    NASA Astrophysics Data System (ADS)

    1990-01-01

    The oceans are the world's largest solar energy collector and storage system. Covering 71 percent of the earth's surface, they collect and store this energy as waves, currents, and thermal and salinity gradients. The purpose of the U.S. Department of Energy's (DOE) Ocean Energy Technology (OET) Program is to develop techniques that harness this ocean energy cost effectively and in a way that does not harm the environment. The program seeks to develop ocean energy technology to a point where industry can accurately assess whether the technology is a viable energy conversion alternative, or supplement, to current power generating systems. In past studies, DOE identified ocean thermal energy conversion (OTEC), which uses the temperature difference between warm surface water and cold deep water, as the most promising of the ocean energy technologies. As a result, the OET Program is concentrating on research that advances the OTEC technology. The program also continues to monitor and study developments in wave energy, ocean current, and salinity gradient concepts; but it is not actively developing these technologies now.

  14. Internal tide oceanic tomography

    NASA Astrophysics Data System (ADS)

    Zhao, Zhongxiang

    2016-09-01

    A concept of internal tide oceanic tomography (ITOT) is proposed to monitor ocean warming on a global scale. ITOT is similar to acoustic tomography, but that work waves are internal tides. ITOT detects ocean temperature changes by precisely measuring travel time changes of long-range propagating internal tides. The underlying principle is that upper ocean warming strengthens ocean stratification and thus increases the propagation speed of internal tides. This concept is inspired by recent advances in observing internal tides by satellite altimetry. In particular, a plane wave fit method can separately resolve multiple internal tidal waves and thus accurately determines the phase of each wave. Two examples are presented to demonstrate the feasibility and usefulness of ITOT. In the eastern tropical Pacific, the yearly time series of travel time changes of the M2 internal tide is closely correlated with the El Niño-Southern Oscillation index. In the North Atlantic, significant interannual variations and bidecadal trends are observed and consistent with the changes in ocean heat content measured by Argo floats. ITOT offers a long-term, cost-effective, environmentally friendly technique for monitoring global ocean warming. Future work is needed to quantify the accuracy of this technique.

  15. 50 CFR 679.64 - Harvesting sideboard limits in other fisheries.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Pacific ocean perch. (A) The Aleutian Islands Pacific ocean perch harvest limit will be equal to the 1996 through 1997 aggregate retained catch of Aleutian Islands Pacific ocean perch by catcher/processors listed... sum of the Aleutian Islands Pacific ocean perch catch in 1996 and 1997 multiplied by the remainder...

  16. 50 CFR 679.64 - Harvesting sideboard limits in other fisheries.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Pacific ocean perch. (A) The Aleutian Islands Pacific ocean perch harvest limit will be equal to the 1996 through 1997 aggregate retained catch of Aleutian Islands Pacific ocean perch by catcher/processors listed... sum of the Aleutian Islands Pacific ocean perch catch in 1996 and 1997 multiplied by the remainder...

  17. 50 CFR 679.64 - Harvesting sideboard limits in other fisheries.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Pacific ocean perch. (A) The Aleutian Islands Pacific ocean perch harvest limit will be equal to the 1996 through 1997 aggregate retained catch of Aleutian Islands Pacific ocean perch by catcher/processors listed... sum of the Aleutian Islands Pacific ocean perch catch in 1996 and 1997 multiplied by the remainder...

  18. Dust and Ocean Plants

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Adding iron to the diet of marine plant life has been shown in shipboard experiments to boost the amount of carbon-absorbing phytoplankton in certain parts of the world's oceans. A new study promises to give scientists their first global picture of the extent of these unique 'iron-limited' ocean regions, an important step in understanding how the ocean's biology controls the flow of carbon between the atmosphere and the ocean. The new study by researchers at NASA's Goddard Space Flight Center and the Department of Energy's Oak Ridge National Laboratory was presented at the American Geophysical Union's annual meeting in San Francisco on Friday, Dec. 15, 2000. Oceanic phytoplankton remove nearly as much carbon from the atmosphere each year as all land-based plants. Identifying the location and size of nutrient-limited areas in the open ocean has challenged oceanographers for nearly a century. The study pinpointed iron-limited regions by seeing which phytoplankton-rich areas of the world's oceans were also areas that received iron from wind-blown dust. In this map, areas with high levels of chlorophyll from phytoplankton and high levels of dust deposition (high correlation coefficients) are indicated in dark brown. Dust deposition was calculated by a 3-year modelled climatology for the years 1996-1998. The chlorophyll measurements are from 1998 observations from the SeaWiFS (Sea-viewing Wide Field-of-view Sensor) instrument on the OrbView-2 satellite. 'Global, satellite-based analyses such as this gives us insight into where iron deposition may be limiting ocean biological activity,' says lead author David Erickson of Oak Ridge National Laboratory's Computer Science and Mathematics Division. 'With this information we will be able to infer how the ocean productivity/iron deposition relationship might shift in response to climate change.' Map Source: David Erickson, Oak Ridge National Laboratory's Computer Science and Mathematics Division

  19. Ophiolites and oceanic crust

    USGS Publications Warehouse

    Moores, E.M.; Jackson, E.D.

    1974-01-01

    OPHIOLITES consist of a pseudostratiform sequence, of harzburgite, tectonite, ultramafic and mafic cumulates sometimes including gabbro and quartz diorite (plagiogranite) intrusions, dolerite dyke swarms, pillow lava 1, and deep-sea sediments2-4. This assemblage occurs in all Phanerozoic mountain systems and is interpreted as fossil oceanic crust and uppermost mantle5-10. Outstanding problems include differences between the chemical properties of Ophiolites and rocks thought to represent present-day oceanic crust11,12, the lack in some complexes of recognised dyke swarms or cumulates, and the relative thinness of ophiolite mafic rocks compared with standard oceanic crustal sections5,8,13. ?? 1974 Nature Publishing Group.

  20. Ocean margins workshop

    SciTech Connect

    1990-12-31

    The Department of Energy (DOE) is announcing the refocusing of its marine research program to emphasize the study of ocean margins and their role in modulating, controlling, and driving Global Change phenomena. This is a proposal to conduct a workshop that will establish priorities and an implementation plan for a new research initiative by the Department of Energy on the ocean margins. The workshop will be attended by about 70 scientists who specialize in ocean margin research. The workshop will be held in the Norfolk, Virginia area in late June 1990.

  1. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield

    USGS Publications Warehouse

    Gabriel, M.C.; Kolka, R.; Wickman, T.; Nater, E.; Woodruff, L.

    2009-01-01

    The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue concentration and a total of 45 watershed and water chemistry parameters were evaluated for two separate years: 2005 and 2006. Results show agreement with other studies where watershed area, lake water pH, nutrient levels (specifically dissolved NO3--N) and dissolved iron are important factors controlling and/or predicting fish THg level. Exceeding all was the strong dependence of yellow perch THg level on soil A-horizon THg and, in particular, soil O-horizon THg concentrations (Spearman ?? = 0.81). Soil B-horizon THg concentration was significantly correlated (Pearson r = 0.75) with lake water THg concentration. Lakes surrounded by a greater percentage of shrub wetlands (peatlands) had higher fish tissue THg levels, thus it is highly possible that these wetlands are main locations for mercury methylation. Stepwise regression was used to develop empirical models for the purpose of predicting the spatial variation in yellow perch THg over the studied region. The 2005 regression model demonstrates it is possible to obtain good prediction (up to 60% variance description) of resident yellow perch THg level using upland soil O-horizon THg as the only independent variable. The 2006 model shows even greater prediction (r2 = 0.73, with an overall 10??ng/g [tissue, wet weight] margin of error), using lake water dissolved iron and watershed area as the only model independent variables. The developed regression models in this study can help with interpreting THg concentrations in low trophic level fish species for untested lakes of the greater Superior National Forest and surrounding Boreal ecosystem. ?? 2009 Elsevier B.V.

  2. Distribution of cadmium, mercury, and lead in different body parts of Baltic herring (Clupea harengus) and perch (Perca fluviatilis): implications for environmental status assessments.

    PubMed

    Boalt, Elin; Miller, Aroha; Dahlgren, Henrik

    2014-01-15

    For heavy metals, quality standards indicating good environmental status are designed to evaluate concentrations in the whole fish body, whereas monitoring of metals is often conducted using muscle or liver tissue. As most metals accumulate at different rates in different parts of fish, data should be adjusted to reflect whole fish body concentrations; however, this requires knowledge on distribution of metal concentrations within fish. Here, concentrations of cadmium, mercury, and lead were analyzed in the liver, muscle and whole fish of herring and perch to create conversion factors for transformation of heavy metal concentrations between these tissues. Species-specific accumulation of metals between muscle, liver, and whole fish were observed. Relationships between different tissues were used to recalculate data from monitoring programs in the Baltic Sea region. Based on whole fish concentrations, environmental status for cadmium and mercury in herring improved compared to assessments based on muscle or liver concentrations alone.

  3. Coast-ocean-atmosphere-ocean mesoscale interaction

    NASA Technical Reports Server (NTRS)

    Atlas, D.; Chou, S. H.

    1982-01-01

    In the case of cold air outbreaks, the combination of the coastal shape and the sea surface temperature (SST) pattern have a profound effect in establishing a low level mesoscale atmospheric circulation as a result of differential heating due to both variations in overwater path length and the SST. A convergence (or divergence) line then forms along a line exactly downwind of the major bend in the coastline. All this is consistent with the structure of the cloud patterns seen in a high resolution Landsat picture of the cloud streets and the major features are simulated well with a boundary layer model. The dominant convergence line is marked by notably larger clouds. To its east the convective roll clouds grow downstream in accord with the deepening of the boundary layer. To its west (i.e., coastal side) where the induced pressure field forces a strong westerly component in the boundary layer, the wind shear across the inversion gives rise to Kelvin-Helmholtz waves and billow clouds whose orientation is perpendicular to the shear vector and to the major convergence line. The induced mesoscale circulation will feedback on the ocean by intensifying the wind generated ocean wave growth and altering their orientation. Coastal cyclogenesis is due in large part not only to the fluxes of heat and moisture from the ocean, but particularly to the differential heating and moistening of the boundary layer air when the air trajectories pass over a well defined pattern of SST.

  4. Geography and Weather: OCEANS.

    ERIC Educational Resources Information Center

    Collins, H. Thomas; Mogil, H. Michael

    1990-01-01

    Provided are suggestions for 23 different activities which can be used to discuss and investigate ocean currents and how they affect human activity. Several maps and charts accompany the activities. A list of 15 resources is included. (CW)

  5. Oceanic Basement Probed

    ERIC Educational Resources Information Center

    Cann, J. R.; Moore, David G.

    1978-01-01

    Summarizes findings of the deep sea drilling project at Scripps Institute of Oceanology. Results of Atlantic and Pacific Ocean drillings in terms of the composition and properties of the sea floor are discussed. (CP)

  6. Isolation over 35 years in a heated biotest basin causes selection on MHC class IIß genes in the European perch (Perca fluviatilis L.)

    PubMed Central

    Björklund, Mats; Aho, Teija; Behrmann-Godel, Jasminca

    2015-01-01

    Genes that play key roles in host immunity such as the major histocompatibility complex (MHC) in vertebrates are expected to be major targets of selection. It is well known that environmental conditions can have an effect on host–parasite interactions and may thus influence the selection on MHC. We analyzed MHC class IIß variability over 35 years in a population of perch (Perca fluviatilis) from the Baltic Sea that was split into two populations separated from each other. One population was subjected to heating from cooling water of a nuclear power plant and was isolated from the surrounding environment in an artificial lake, while the other population was not subjected to any change in water temperature (control). The isolated population experienced a change of the allelic composition and a decrease in allelic richness of MHC genes compared to the control population. The two most common MHC alleles showed cyclic patterns indicating ongoing parasite–host coevolution in both populations, but the alleles that showed a cyclic behavior differed between the two populations. No such patterns were observed at alleles from nine microsatellite loci, and no genetic differentiation was found between populations. We found no indications for a genetic bottleneck in the isolated population during the 35 years. Additionally, differences in parasitism of the current perch populations suggest that a change of the parasite communities has occurred over the isolation period, although the evidence in form of in-depth knowledge of the change of the parasite community over time is lacking. Our results are consistent with the hypothesis of a selective sweep imposed by a change in the parasite community. PMID:25897384

  7. Survival, blood osmolality, and gill morphology of juvenile yellow perch, rock bass, black crappie, and largemouth bass exposed to acidified soft water

    SciTech Connect

    McCormick, J.H.; Jensen, K.M.; Leino, R.L.

    1989-01-01

    When exposed to a range of pH from 7.0 to 4.0 in soft water (1 mg Ca(2+)/L), juvenile rock bass Ambloplites rupestris, black crappie Pomoxis nigromaculatus, and largemouth bass Micropterus salmoides showed a capacity to osmoregulate and survive for up to 30 d at pH 4.5 and above. Juvenile yellow perch Perca flavescens maintained osmoregulatory control through 58 d at pH 5.0. All four species lost osmoregulatory control at pH 4.0, and death of fish ensued within a few days after blood osmolality declined to about 200 mosmol/kg or less (normal values, about 300 mosmol/kg). After 58 d of exposure of pH 4.0, mean blood osmolality of yellow perch was 218 mosmol/kg, and these fish were severely emaciated and moribund. Rock bass, black crappie, and largemouth bass all died by days 29, 16, and 9, respectively, when exposed to pH 4.0. Examination of gills showed progressively increased pathology with longer exposures to lower than normal pH. Among fish exposed to low pH, gill hyperplasia was present most often, but epithelial hypertrophy, chloride-cell proliferation, chloride-cell degeneration, edema, and vacuolization of the tissues also were observed. Morphological changes that were observed in the three centrarchids at pH values above pH 4.0 suggested that gill pathology may be a more sensitive indicator of potentially lethal acid stress than blood osmolality.

  8. Isolation over 35 years in a heated biotest basin causes selection on MHC class IIß genes in the European perch (Perca fluviatilis L.).

    PubMed

    Björklund, Mats; Aho, Teija; Behrmann-Godel, Jasminca

    2015-04-01

    Genes that play key roles in host immunity such as the major histocompatibility complex (MHC) in vertebrates are expected to be major targets of selection. It is well known that environmental conditions can have an effect on host-parasite interactions and may thus influence the selection on MHC. We analyzed MHC class IIß variability over 35 years in a population of perch (Perca fluviatilis) from the Baltic Sea that was split into two populations separated from each other. One population was subjected to heating from cooling water of a nuclear power plant and was isolated from the surrounding environment in an artificial lake, while the other population was not subjected to any change in water temperature (control). The isolated population experienced a change of the allelic composition and a decrease in allelic richness of MHC genes compared to the control population. The two most common MHC alleles showed cyclic patterns indicating ongoing parasite-host coevolution in both populations, but the alleles that showed a cyclic behavior differed between the two populations. No such patterns were observed at alleles from nine microsatellite loci, and no genetic differentiation was found between populations. We found no indications for a genetic bottleneck in the isolated population during the 35 years. Additionally, differences in parasitism of the current perch populations suggest that a change of the parasite communities has occurred over the isolation period, although the evidence in form of in-depth knowledge of the change of the parasite community over time is lacking. Our results are consistent with the hypothesis of a selective sweep imposed by a change in the parasite community. PMID:25897384

  9. Effects of dietary linseed oil on innate immune system of Eurasian perch and disease resistance after exposure to Aeromonas salmonicida achromogen.

    PubMed

    Geay, F; Mellery, J; Tinti, E; Douxfils, J; Larondelle, Y; Mandiki, S N M; Kestemont, P

    2015-12-01

    This study was designated to investigate the effects of dietary fish oil (FO diet) replacement by linseed oil (LO diet) on regulation of immune response and disease resistance in Eurasian perch (Perca fluviatilis). A control diet containing fish oil (FO = cod liver oil) and characterized by high levels of n-3 high LC-PUFA (6% EPA, 7.5% of total fatty acids (FAs)) was compared to linseed oil diet (LO diet) composed of low LC-PUFA contents (1% EPA, 2.3% DHA of total FAs) but high C18 fatty acids levels. The experiment was conducted in quadruplicate groups of 80 fish each. After 10 weeks of feeding, the innate immune status was evaluated in various organs (liver, spleen, and head-kidney) (feeding condition). Two days later, a bacterial challenge was performed on fish from 2 rearing conditions: fish infected with Aeromonas salmonicida (bacteria condition) and fish injected with sterile medium but maintained in the same flow system that fish challenged with bacteria (sentinel condition). Three days after injection of bacteria, a significant decrease of lymphocyte, thrombocyte and basophil populations was observed while neutrophils were not affected. In addition, plasma lysozyme activity and reactive oxygen species production in kidney significantly increased in fish challenged with A. salmonicida while the plasma alternative complement pathway activity was not affected. Increase of plasma lysozyme activity as well as reactive oxygen species production in spleen and kidney of sentinel fish suggest that these immune defenses can also be activated, but at lower bacteria concentration than infected fish. No differences in leucocyte populations, plasma lysozyme and alternative complement pathway activities were observed between dietary treatments. Similarly, expression of genes related to eicosanoid synthesis in liver were not affected by the dietary oil source but were strongly stimulated in fish challenged with A. salmonicida. These findings demonstrated that the use of

  10. Clinton releases oceans report

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    U.S. President Bill Clinton is trying to beat the clock on the January 20 close of his administration by maintaining a flurry of activity on resource and conservation issues.During a December 4 speech in Washington, D.C., he released a broad-ranging report by the Presidents Panel on Ocean Exploration, entitled “Discovering Earth's Final Frontier: A U.S. Strategy for Ocean Exploration.”

  11. Measurements of ocean color

    NASA Technical Reports Server (NTRS)

    Hovis, W. A.

    1972-01-01

    An airborne instrument for determining ocean color and measurements made with the instrument are discussed. It was concluded that a clear relationship exists between the chlorophyll concentration and the color of the water. High altitude measurements from 50,000 feet are described and the effects of atmospheric scattering on the energy reaching the sensor are examined. The measured spectrum of ocean color at high and low altitudes is plotted.

  12. Ocean microbial metagenomics

    NASA Astrophysics Data System (ADS)

    Kerkhof, Lee J.; Goodman, Robert M.

    2009-09-01

    Technology for accessing the genomic DNA of microorganisms, directly from environmental samples without prior cultivation, has opened new vistas to understanding microbial diversity and functions. Especially as applied to soils and the oceans, environments on Earth where microbial diversity is vast, metagenomics and its emergent approaches have the power to transform rapidly our understanding of environmental microbiology. Here we explore select recent applications of the metagenomic suite to ocean microbiology.

  13. Ocean circulation studies

    NASA Technical Reports Server (NTRS)

    Koblinsky, C. J.

    1984-01-01

    Remotely sensed signatures of ocean surface characteristics from active and passive satellite-borne radiometers in conjunction with in situ data were utilized to examine the large scale, low frequency circulation of the world's oceans. Studies of the California Current, the Gulf of California, and the Kuroshio Extension Current in the western North Pacific were reviewed briefly. The importance of satellite oceanographic tools was emphasized.

  14. BCube Ocean Scenario

    NASA Astrophysics Data System (ADS)

    Santoro, Mattia; Schofield, Oscar; Pearlman, Jay; Nativi, Stefano

    2015-04-01

    To address complex Earth system issues such as climate change and water resources, geoscientists must work across disciplinary boundaries; this requires them to access data outside of their fields. Scientists are being called upon to find, access, and use diverse and voluminous data types that are described with semantics. Within the framework of the NSF EarthCube programme, the BCube project (A Broker Framework for Next Generation Geoscience) is addressing the need for effective and efficient multi-disciplinary collaboration and interoperability through the advancement of brokering technologies. BCube develops science scenarios as key elements in providing an environment for demonstrating capabilities, benefits, and challenges of the developed e-infrastructure. The initial focus is on hydrology, oceans, polar and weather, with the intent to make the technology applicable and available to all the geosciences. This presentation focuses on the BCube ocean scenario. The purpose of this scenario is to increase the understanding of the ocean dynamics through incorporation of a wide range of in-situ and satellite data into ocean models using net primary productivity as the initial variable. The science scenario aims to identify spatial and temporal domains in ocean models, and key ecological variables. Field data sets and remote observations data sets from distributed and heterogeneous systems are accessed through the broker and will be incorporated into the models. In this work we will present the achievements in the development of the BCube ocean scenario.

  15. Flexible ocean upwelling pipe

    DOEpatents

    Person, Abraham

    1980-01-01

    In an ocean thermal energy conversion facility, a cold water riser pipe is releasably supported at its upper end by the hull of the floating facility. The pipe is substantially vertical and has its lower end far below the hull above the ocean floor. The pipe is defined essentially entirely of a material which has a modulus of elasticity substantially less than that of steel, e.g., high density polyethylene, so that the pipe is flexible and compliant to rather than resistant to applied bending moments. The position of the lower end of the pipe relative to the hull is stabilized by a weight suspended below the lower end of the pipe on a flexible line. The pipe, apart from the weight, is positively buoyant. If support of the upper end of the pipe is released, the pipe sinks to the ocean floor, but is not damaged as the length of the line between the pipe and the weight is sufficient to allow the buoyant pipe to come to a stop within the line length after the weight contacts the ocean floor, and thereafter to float submerged above the ocean floor while moored to the ocean floor by the weight. The upper end of the pipe, while supported by the hull, communicates to a sump in the hull in which the water level is maintained below the ambient water level. The sump volume is sufficient to keep the pipe full during heaving of the hull, thereby preventing collapse of the pipe.

  16. The Ocean: Our Future

    NASA Astrophysics Data System (ADS)

    Independent World Commission On The Oceans; Soares, Mario

    1998-09-01

    The Ocean, Our Future is the official report of the Independent World Commission on the Oceans, chaired by Mário Soares, former President of Portugal. Its aim is to summarize the very real problems affecting the ocean and its future management, and to provide imaginative solutions to these various and interlocking problems. The oceans have traditionally been taken for granted as a source of wealth, opportunity and abundance. Our growing understanding of the oceans has fundamentally changed this perception. We now know that in some areas, abundance is giving way to real scarcity, resulting in severe conflicts. Territorial disputes that threaten peace and security, disruptions to global climate, overfishing, habitat destruction, species extinction, indiscriminate trawling, pollution, the dumping of hazardous and toxic wastes, piracy, terrorism, illegal trafficking and the destruction of coastal communities are among the problems that today form an integral part of the unfolding drama of the oceans. Based on the deliberations, experience and input of more than 100 specialists from around the world, this timely volume provides a powerful overview of the state of our water world.

  17. Simple ocean carbon cycle models

    SciTech Connect

    Caldeira, K.; Hoffert, M.I.; Siegenthaler, U.

    1994-02-01

    Simple ocean carbon cycle models can be used to calculate the rate at which the oceans are likely to absorb CO{sub 2} from the atmosphere. For problems involving steady-state ocean circulation, well calibrated ocean models produce results that are very similar to results obtained using general circulation models. Hence, simple ocean carbon cycle models may be appropriate for use in studies in which the time or expense of running large scale general circulation models would be prohibitive. Simple ocean models have the advantage of being based on a small number of explicit assumptions. The simplicity of these ocean models facilitates the understanding of model results.

  18. Ocean Data Acquisition System

    NASA Technical Reports Server (NTRS)

    Johnson, B.; Cavanaugh, J.; Smith, J.; Esaias, W.

    1988-01-01

    The Ocean Data Acquisition System (ODAS) is a low cost instrument with potential commercial application. It is easily mounted on a small aircraft and flown over the coastal zone ocean to remotely measure sea surface temperature and three channels of ocean color information. From this data, chlorophyll levels can be derived for use by ocean scientists, fisheries, and environmental offices. Data can be transmitted to shipboard for real-time use with sea truth measurements, ocean productivity estimates and fishing fleet direction. The aircraft portion of the system has two primary instruments: an IR radiometer to measure sea surface temperature and a three channel visible spectro-radiometer for 460, 490, and 520 nm wavelength measurements from which chlorophyll concentration can be derived. The aircraft package contains a LORAN-C unit for aircraft location information, clock, on-board data processor and formatter, digital data storage, packet radio terminal controller, and radio transceiver for data transmission to a ship. The shipboard package contains a transceiver, packet terminal controller, data processing and storage capability, and printer. Both raw data and chlorophyll concentrations are available for real-time analysis.

  19. Ocean energy systems

    NASA Astrophysics Data System (ADS)

    1984-04-01

    The Johns Hopkins University Applied Physics Laboratory is engaged in developing ocean thermal energy conversion (OTEC) systems that are to provide synthetic fuels or an energy intensive product such as ammonia or aluminum. The work also includes assessment and design concepts for hybrid plants, such as geothermal-OTEC plants. The laboratory also has a technical advisory role with respect to DOE/DOET's management of the preliminary design activity of an industry team headed by Ocean Thermal Corporation that is designing an OTEC pilot plant that could be built in shallow water off the shore of Oahu, Hawaii. In addition, the Laboratory is now taking part in a program to evaluate and test the pneumatic wave energy conversion system, an ocean energy device consisting of a turbine that is air driven as a result of wave action in a chamber.

  20. Sub-Ocean Drilling

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The National Science Foundation (NSF) initialized a new phase of exploration last year, a 10 year effort jointly funded by NSF and several major oil companies, known as the Ocean Margin Drilling Program (OMDP). The OMDP requires a ship with capabilities beyond existing drill ships; it must drill in 13,000 feet of water to a depth 20,000 feet below the ocean floor. To meet requirements, NSF is considering the conversion of the government-owned mining ship Glomar Explorer to a deep ocean drilling and coring vessel. Feasibility study performed by Donhaiser Marine, Inc. analyzed the ship's characteristics for suitability and evaluated conversion requirement. DMI utilized COSMIC's Ship Motion and Sea Load Computer program to perform analysis which could not be accomplished by other means. If approved for conversion, Glomar Explorer is expected to begin operations as a drillship in 1984.