Spelling suggestions: "subject:"chinook"" "subject:"shinook""
11 |
Ecological influence of bacterial kidney disease on juvenile spring chinook salmon : effects on predator avoidance ability, smoltification, and physiological responses to stressMesa, Matthew G. 28 January 1999 (has links)
Juvenile chinook salmon (Oncorhynchus tshawytscha) were experimentally infected with Renibacterium salmoninarum (Rs), the causative agent of bacterial kidney disease (BKD), to investigate the effects of BKD on three aspects of juvenile salmonid performance: (1) predator avoidance ability; (2) smoltification; and (3) physiological responses to stress. For these experiments, fish with different Rs-infection profiles (created by using an immersion challenge method) were sampled to assess physiological change and subjected to various performance tests during disease progression.
When equal numbers of Rs-challenged and unchallenged fish were subjected to predation by northern pikeminnow (Ptychocheilus oregonensis) or smallmouth bass
(Micropterus dolomieui), Rs-challenged fish were eaten in significantly greater numbers
than controls by nearly two to one.
A progressively worsening infection with Rs did not alter the normal changes in gill ATPase and condition factor associated with smoltification in juvenile chinook salmon. A dramatic proliferation of BKD was associated with maximal responses of indicators of smoltification, suggesting that the process of smoltification itself can trigger outbreaks of disease.
When Rs-infected fish were subjected to three 60-s bouts of severe handling that were separated by 48-72 h, this experience did not lead to higher infection levels or increased mortality when compared to diseased fish that did not receive the stressors. Furthermore, the kinetics of plasma cortisol, glucose, and lactate over 24-h following each stressor were similar between fish with moderate to high BKD and those that had low or no detectable infection. Fish with moderate to high Rs infections had higher titers of cortisol and lactate prior to each application of the stressor and were also unable to consistently elicit a significant hyperglycemia in response to the stressors when compared to fish with low infection levels.
During all experiments, fish consistently developed decreased hematocrits and blood glucose levels and increased levels of cortisol and lactate as the disease worsened, indicating that BKD is stressful, particularly during the later stages.
Collectively, these results illustrate the impact of BKD on juvenile salmonids and have also ascribed some ecological significance to this disease beyond that of direct pathogen-related mortality. / Graduation date: 1999
|
12 |
Inbreeding and its consequences for genetic variation and early life history in chinook salmon /Wang, Shizhen, January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 108-138).
|
13 |
Long-term effects of alternative hatchery mating practices and size selective fishing on age and sex composition of Chinook salmon populations returning to hatcheries /Chen, Yaming. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 76-81). Also available via Humboldt Digital Scholar.
|
14 |
Optimization models for understanding migration patterns of juvenile chinook salmon /Hinrichsen, Richard A., January 1994 (has links) (PDF)
Thesis (Ph. D.)--University of Washington, 1994. / Vita. Includes bibliographical references (leaves [191]-210).
|
15 |
Fish-holding-associated stress in Sacramento River chinook salmon (Oncorhynchus tshawytscha) at south delta fish salvage operations effects on plasma constituents, swimming performance, and predator avoidance /Portz, Donald Edward. January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of California, Davis, 2008. / Includes bibliographical references (p. 133-150).
|
16 |
Life histories of juvenile chinook salmon in the Columbia River estuary : 1916 to the present /Burke, Jennifer L. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaves 79-88). Also available online.
|
17 |
Influence of incision location on transmitter loss, healing, incision length, suture retention, and growth of juvenile Chinook salmonPanther, Jennifer Lynne. January 2010 (has links) (PDF)
Thesis (M.S. in environmental science)--Washington State University, May 2010. / Title from PDF title page (viewed on May 11, 2010). School of Earth and Environmental Science." Includes bibliographical references (p. 35-39).
|
18 |
Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collectionMayer, Kent Corey 16 April 2002 (has links)
Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin
are listed as endangered under the Endangered Species Act. The typical life history of spring
chinook salmon is semelparous. An experiment was performed to see if mature male spring
chinook salmon parr could be reconditioned after hand-spawning and spawned in successive
years. The mature male parr were part of a 1997 and 1998 cohort of captive broodstock from
the Grande Ronde River Basin in Oregon. Force-feeding was combined with volitional
feeding in an attempt to inhibit senescence and increase survival time after spawning. The
viscerosomatic index, fat and protein contents increased with survival time after spawning
for both cohorts. There was a significant relationship between percent weight change and
survival time for the 1997 cohort (p<0.001). Force-feeding had no effect on survival time
after spawning for the 1997 cohort (p=0.074) or the 1998 cohort (p=0.178). Fat content,
weight gain and survival time indicated that the reconditioning process was observable in the
1997 cohort at 77 days after spawning and was cyclical, resulting in a physiological response
which allowed male chinook salmon to spawn in successive years. Fertilization trials with
three reconditioned males yielded a fertilization success rate of 96.9% compared to 95.7% for
4-year old, anadromous male spring chinook salmon (p=0.152), measured as production of
eyed-embryos. This experiment provides new knowledge of plasticity in the reproductive
biology of male, stream-type, spring chinook salmon. Reconditioning and spawning male
chinook salmon parr in successive years could be used to help maximize genetic diversity and
aid in the recovery of endangered Oncorhynchus populations. / Graduation date: 2002
|
19 |
Growth and the plasticity of smolting in Chinook salmon /Beckman, Brian Robert. January 2002 (has links)
Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 186-216).
|
20 |
Loma salmonae in Chinook salmon (Oncorhynchus tshawytscha): improving detection, preventing infection, and increasing our understanding of the host response to a microsporidian parasiteThomson, Catherine Ann 30 September 2013 (has links)
Loma salmonae is a microsporidian parasite that infects economically important Chinook salmon (Oncorhynchus tshawytscha) farmed in British Columbia, Canada. Here a variety of research efforts aimed at improving early detection and diagnostic tools, developing preventative strategies, and increasing understanding of the parasite/host interactions are presented. First, the development of chicken-derived polyclonal antibodies (IgY) specific for L. salmonae is described. These antibodies have proven useful for immunohistochemical detection of parasites very early in the infection process. Next, the immune-modulating effects of intra-peritoneal β-glucan inoculation of Chinook salmon are presented. Intensity of L. salmonae infection was significantly reduced in fish inoculated with β-glucan 3 weeks prior to parasite exposure, although prevalence was not reduced in these fish. Gene expression analysis of head kidney from glucan-inoculated fish measured at 1, 2 and 3 weeks post-inoculation (PI) revealed that the majority of differential expression occurred at 1 week. Pathways related to antioxidant defence, innate immune responses, antigen presentation, as well as oxidative metabolism were up-regulated in glucan-inoculated fish at 1 week PI. Finally, temporal gene-expression
analysis on gill and kidney tissue from Chinook salmon infected with L. salmonae is described. Analysis at 4 weeks post-exposure (PE) in the gill revealed an early up-regulation of gas transport, whereas numerous pathways including oxidative metabolism, antioxidant defences, monooxygenases and immune receptors were down-regulated in the gill at the same time point. Similarly, oxidative metabolism, antioxidant defences, and monooxygenases were down-regulated in the kidney at 4 weeks PE. However, there is evidence for a developing immune response over time. Antigen processing and presentation pathways were up-regulated in the kidney at 4 weeks and in both tissues at 8 weeks PE. In addition a number of immune receptors and genes involved with innate immune functions were also up-regulated at 4 and 8 weeks PE in the kidney. / Graduate / 0306
|
Page generated in 0.0301 seconds