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Distribution, abundance, and emigration of juvenile steelhead (Oncorhynchus mykiss), and analysis of stream habitat in the Steamboat Creek Basin, Oregon /Dambacher, Jeffery M. January 1991 (has links)
Thesis (M.S.)--Oregon State University, 1991. / Typescript (photocopy). Includes bibliographical references (leaves 100-106). Also available via the World Wide Web.
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Steelhead trout otoliths for age, race, and stock analysis /McKern, John L. January 1971 (has links)
Thesis (M.S.)--Oregon State University, 1971. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.
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Development of a standard weight equation for juvenile steelhead trout and effects of temperature, turbidity, and steelhead trout biomass on relative weight /McLaughlin, Katherine D. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2009. / Includes bibliographical references (leaves 49-57). Also available via Humboldt Digital Scholar.
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Effects of acute stress and exercise on subsequent seawater adaptation and cortisol dynamics in juvenile steelhead trout (Oncorhynchus mykiss)Liebert, Anja M. 05 February 2004 (has links)
The present study investigated the effects of stress and exercise on
seawater (SW) adaptation and cortisol dynamics in juvenile steelhead
(Oncorhynchus mykiss). To examine the effects of stress, fish acclimated to
freshwater (FW) were subjected for 3 hours to confinement stress in FW, and
subsequently SW (25 ppt) was introduced to all tanks. Fish were sampled
immediately after the stress treatment, and 1, 7, and 14 days after introduction of
SW. Electrolytes, cortisol, glucose and lactate followed the typical pattern that we
expected after stress treatment in FW. Fish regained osmotic balance within 24
hours. Glucose concentrations were increasing throughout the experiment and
lactate levels stayed elevated during the time spent in SW. IGF-1 did not show
an immediate response to stress but after transfer to SW we detected
significantly higher concentrations for control fish at days 1 and 14. The
differences in IGF-1 levels between stressed and control fish are not reflected in
SW adaptability but positive correlations between IGF-1 and electrolyte levels in
control fish may indicate its role for osmoregulation. Confinement stress did not
impair feed intake subsequently in SW, but our results suggest that feed intake
was suppressed by the change of the media from FW to SW.
The second study investigated the effects of exercise treatment in FW on
SW adaptation and cortisol dynamics in juvenile steelhead. Plasma cortisol and
in vitro cortisol secretion by interrenal cells after a 24 hr SW challenge test were
neither affected by moderate exercise nor by water temperature (13��C, 21��C),
however, plasma osmolality was lower in exercised fish compared to unexercised
fish. Half-life (T[subscript 1/2]) of ��H-cortisol was shorter in fish exposed to exercise whereas
metabolic clearance rate (MCR) did not respond to exercise treatment. Uptake
and retention of corticosteroids in liver and gall bladder were enhanced in
exercised fish, and retention of corticosteroids in muscle tissue was longer in
unexercised fish. Our findings suggest that exercise likely decreases stress
levels in fish and improves the adaptation to seawater (SW) in juvenile steelhead. / Graduation date: 2004
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The mating system of steelhead and the effect of length and arrival date on steelhead reproductive success /Seamons, Todd R. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 168-178).
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The relative effects of Ceratomyxa shasta on crosses of resistant and susceptible stocks of summer steelheadWade, Mark 15 August 1986 (has links)
Crosses were made between a stock of summer steelhead (Salmo
gairdneri) known to be resistant to infection by Ceratomyxa
shasta and stocks of summer steelhead known to be susceptible.
Ceratomyxosis, the disease caused by C. shasta was initiated by
exposure to Willamette River water. I found that the crosses
were intermediate in susceptibility to ceratomyxosis relative to
the parental stocks. There was no difference in susceptibility
to ceratomyxosis between reciprocal crosses of the same stocks.
Persistence of moderate susceptibility in the F₂ generation of
experimental stock crosses and examples from both wild and
hatchery stocks of mixed ancestry indicate long term disease
problems may result from introductions of less adapted, foreign stocks. / Graduation date: 1987
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Sex and life stage sensitivity of rainbow trout to xenoestrogensCarlson, David B., 1970- 20 July 1998 (has links)
Numerous natural and anthropogenic chemicals interact with endocrine systems of
animals. The most widely studied of these endocrine active chemicals (EACs) are
estrogen receptor agonists and antagonists. Because of the many important roles of
estrogens in animals, xenoestrogens have the potential to impact environmental health. It
has been proposed that xenoestrogen contaminants are responsible for recent increases in
estrogen dependent human diseases and sexual and developmental abnormalities in
wildlife. Aquatic species are particularly susceptible to persistent EACs that accumulate in
sediments and biomagnify along trophic levels. Rainbow trout, Oncorhynchus mykiss,
commonly used in biomedical research and as a sentinel species, was chosen as a model
for studying mechanisms of xenoestrogen activity. The aims of this research were to
assess the estrogenic activity of individual persistent, organic contaminants and simple
mixtures in vivo. Emphasis was placed on determining the potential for xenoestrogens to
alter sexual development or to induce sexually dimorphic biochemical responses. Gonadal
abnormalities in trout exposed as embryos to the xenoestrogen o,p'-DDE showed that
xenobiotics can affect trout sexual development. However, the absence of endocrine
disruption by low doses of o,p'-DDE, by the xenoestrogens chlordecone and octylphenol,
or by the anti-androgen p,p'-DDE, suggested that lethality is likely to precede endocrine
disruption in highly exposed, feral salmonid populations. Sexually distinct responses in
immature trout were documented with respect to vitellogenin induction (2 to 4 fold higher
in females) and cytochrome P450 expression. Sex differences occurred only when doses
of estrogens or xenoestrogens were below levels that cause maximal estrogenic responses.
Evidence suggests that estrogen regulation may be fundamentally different in immature
males and females, which may have implications for natural populations exposed to
xenoestrogens. Vitellogenin induction and P450 modulation were responsive to mixtures
of estrogens and xenoestrogens in a manner suggestive of additive activation of estrogen
receptors. Cytochrome P450 dependent induction of lauric acid hydroxylation was
observed for the first time in trout, in response to tamoxifen and mixtures of tamoxifen
and 17��-estradiol. The estrogenic activity of tamoxifen and 4-hydroxy-2',4',6'-trichlorobiphenyl
were greater in vivo than what was predicted by in vitro studies, which
emphasized the need for mechanism based investigations of xenoestrogens in whole
organisms. / Graduation date: 1999
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Movement and mitigation of domestic triploid steelhead trout (Oncorhynchus mykiss) escaped from aquaculture grow-out cages /Bridger, Christopher J. January 2002 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2002. / Bibliography: leaves 88-98.
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Description and prediction of broad-scale spatial variability in expression of anadromy in female Oncorhynchus mykiss in the John Day River, Oregon, USA /Mills, Justin S. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves - ). Also available on the World Wide Web.
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Long-term effects of habitat and management changes on steelhead production results from an individual-based model.Bolduc, Melanie B. January 2006 (has links)
Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: individual-based model, Oncorhyncus mykiss. Includes bibliographical references (p.73-75).
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