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).

Thesis (Ph.D.) in Zoology--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 95-108).

Nuclear microsatellite DNA and mitochondrial DNA variation were examined in coho salmon (Oncorhynchus kisutch) and white sturgeon (Acipenser transmontanus) populations in order to address conservation issues in each species. In coho the goal was to examine genetic structure on a broad scale, in order to facilitate the conservation of genetic resources within the species. Coho salmon were widely sampled across their North American range. In white sturgeon the goal was to characterize population structure within the Fraser River, in order to identify biologically meaningful management units within that system. White sturgeon sampling was restricted to two watersheds (the Fraser and Columbia rivers), allowing much more thorough sampling than was done for coho. For both species, the use of mitochondrial and nuclear markers proved advantageous over examining either marker alone. The coho data revealed two levels of intraspecific variation, and gave the best indication to date regarding how genetic resources might be distributed within this species. The data is useful for protecting this species' ability to evolve. In contrast, the sturgeon data identified four regions within the Fraser River between which migration is limited. The sturgeon data, therefore, facilitate prevention of extirpation of local populations within the Fraser River. / Graduate

Laboratory experiments were conducted to study the effects of dehydro-abietic acid (DHA) on the physiology of the adaptation of sockeye salmon smolts (Oncorhynchus nerka) to sea water. Dehydroabietic acid occurs in the rosin of commercially important coniferous trees and is found in the untreated effluents of the pulp and paper industry at concentrations acutely toxic to salmonids. As this resin acid is known to be one of the more persistent toxic components of kraft mill effluent (KME) and although its concentrations are greatly reduced by biological treatment, DHA is nevertheless discharged in the effluents of the pulp mills situated on the Fraser River system as well as of those located on the coast of British Columbia. As sockeye salmon utilize both the Fraser and Thompson Rivers during their downstream migration, this species may be exposed to DHA before entering the sea. An attempt was made to simulate this situation in the laboratory by exposing sockeye salmon smolts to a sublethal concentration of DHA (0.65 mg/L) in fresh water for 120 h and then transferring them into sea water (28 °/oo) containing no DHA. Hydromineral balance was studied by monitoring changes in plasma osmolality, plasma NA⁺, K⁺ , Ca⁺⁺, Mg⁺⁺ and Cl⁻, blood hematocrit and muscle water content at the end of the freshwater DHA exposure and at 24 h intervals during the adaptation to sea water (120 h). After 24 h in sea water the gill permeability to water and the water transport ability of the gut were also determined. Supportive experiments measured changes in the size of red blood cells, the levels of plasma bilirubin as well as the uptake and tissue distribution of DHA in sockeye salmon smolts. Lipid extracts of various tissues were analyzed for DHA residues by gas chromatography coupled with mass spectrometry (GC-MS). The exposure of sockeye salmon to DHA in fresh water resulted in a hydromineral disturbance characterized by a drop in plasma osmolality, sodium, and chloride, indicating a general hydration which was reflected by increased muscle water content. A lowering of dissolved oxygen to 75% saturation markedly increased the toxicity of DHA and the osmotic imbalance may have been a secondary result of an adaptive respiratory response to a hypoxic stress brought on by DHA exposure. Increases in blood hematocrit were caused by a swelling of the red blood cells related to lowered plasma osmolality. When these fish were transferred to sea water, the hydration was replaced by dehydration and a rise in osmolality was caused by abnormally elevated levels of all the plasma ions. The added salinity stress resulted in some mortality and considerably greater excursions in plasma electrolytes occurred in fish which were experiencing locomotor difficulty. Plasma magnesium showed the greatest elevation and took the longest (96 h) to return to normal levels. Prior DHA exposure increased the permeability of the gill. During acute DHA exposure in fresh water a gradual deterioration in schooling and fright response was followed by hypersensitivity to mechanical stimuli and abnormal swimming behavior. After sublethal exposure, the reduction in schooling and fright response generally became most evident during the first 24 h of sea water adaptation. These results of the study are discussed in terms of the possible roles played by the gills, gut and kidney in the DHA-induced perturbations of hydromineral balance. The implications of the accompanying alterations in behavior are discussed in the context of the ecological survival of sockeye salmon smolts during adaptation to sea water. Residue analyses showed that sockeye salmon accumulated DHA from the water to high levels in the brain (954 x), liver (428 x) and kidney (404 x) as well as in other tissues. The presence of DHA metabolites in the bile, which also contained the highest DHA residues (647.3 μg/g), indicates that the hepatobiliary route is important in the excretion of DHA by fish. The possibility of the bioaccumulation of DHA by fish in the wild is discussed in relation to the setting of water quality criteria for pulp mill effluent. / Science, Faculty of / Zoology, Department of / Graduate

The predatory functional response is one of the important components of the interaction between predator and prey populations. This response has not been measured for fish predators and fish prey, in spite of the demonstrated importance of predation in regulating numbers in populations such as the juvenile salmon system used in this thesis. Laboratory exeriments were conducted to determine the form of the functional response of the prickly sculpin (Cottus asper), a common freshwater predator, to density of sockeye salmon fry, Oncorhynchus nerka. An alternative prey, chum salmon eggs (Oncorhynchus keta), were presented to the predator with the salmon fry, in order to facilitate switching at low fry densities and possibly lead to a sigmoid (type III) response. Initial experiments showed that sculpin feeding rate did not substantially differ from day to night; that in the absence of food, hunger increased to a maximum after about seven days' starvation; and that a density of 400 chum salmon eggs in a 2000 1 tank produced maximum consumption level by sculpins of 160 mm total length. The functional response experiments did not indicate a sigmoid rise in consumption over low fry densities. However, the initial decelerated rise in consumption was followed by an anomalous drop in response and a subsequent rise in response. It is suggested that this may result from the summation of separate responses through different sensory modalities, or from interference with predation by fry at intermediate densities. This shape of functional response may imply a stable local equilibrium at intermediate densities of salmon. Sculpins probably have a significant impact on fry numbers only at very localized points in space and time, such as at the outlets of tidal creeks on a falling tide. / Science, Faculty of / Zoology, Department of / Graduate

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The primary purpose of this study is to investigate the salmon demand of Japanese households. The specific goals are to illuminate the substitutional relationship between salmon and other foods and to examine seasonal and regional differences in salmon demand. To analyze substitutional relationships and seasonal differences, monthly data on consumption by Japanese households are used. An econometric model was developed in which salmon demand was specified with quantity of salmon consumed as the dependent variable and income (food expenditure), price of salmon and the price of possible substitute commodities as independent variables. To investigate the regional differences, five geographically different regions were selected. Analysis was conducted with annual data. Among the findings are that pork may be a substitute commodity for salmon in Japanese households, and that there are clear seasonal and regional differences in terms of salmon demand at the household level in Japan. / Graduation date: 1987

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