Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 114-134). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Washington, 1994. / Vita. Includes bibliographical references (leaves 82-102).

Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 56-63). Also available via Humboldt Digital Scholar.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographic references (leaves [165]-185).

No description available.

Fish diseases and various parameters associated with disease caused mortality of fish were monitored at the Oregon State University Marine Science Center and at a private mariculture facility on Yaquina Bay during a period of five years. Nearly all disease problems observed were caused by Vibrio anguillarum and Vibrio spp. Infection by Vibrio spp. resulted in substantial mortality (as high as 50% of a population) among fish which were immunized against two serotypes of V. anguillarum and among non-immunized fish. Naturally occurring levels of V. anguillarum in Yaquina Bay were determined to be ten or less viable cells per ml water. Effluent water from groups of salmonids with naturally acquired vibriosis contained 1.0 to 4.3 x 10�� viable cells of V. anguillarum per ml. The histopathology associated with naturally acquired and experimentally induced infections of vibriosis in chum salmon fingerlings was described for the two serotypes of V. anguillarum which commonly cause epizootic levels of mortality among salmonids reared at mariculture facilities in the Pacific Northwest United States. Results of these studies indicate that different histopathologic changes are produced by the two serotypes of V. anguillarum. One serotype (referred to as V. anguillarum serotype I) produced a bacteremia in early stages of disease with the following organs and tissues being the main targets: blood, loose connective tissue, kidney, spleen, posterior gastrointestinal tract, and gills. The second serotype (referred to as V. anguillarum serotype II) produced a bacteremia in late stages of disease with the following organs and tissues being main targets: skeletal muscle, cardiac muscle, anterior gastrointestinal tract, posterior gastrointestinal tract, and gills. Vibrio anguillarum serotype I cells were evenly dispersed throughout infected fish tissues while V. anguillarum serotype II formed distinct colonies in tissues of fish. Experimentally induced infections of chum, coho, and chinook salmon were studied to compare the histopathologic changes associated with infections of V. anguillarum serotypes I and II and to obtain. quantitative data concerning some specific effects produced in fish infected with these organisms. Differences in histopathology noted above were observed in all three species of fish when infections of the two serotypes of V. anguillarum were compared. Cellular responses were rarely observed during early or late stages of vibriosis. The data suggest that both serotypes of V. anguillarum used in these studies produce a leukocidin in fish because infected fish had 80% to 95% less leukocytes than non-infected control fish. Extremely high levels of V. anguillarum were shown to be present in fish tissues. Pathology observed in the mucosa of the gastrointenstinal tract of infected fish was apparently related to pH. The anterior gastrointestinal tract was strongly acidic and contained no necrosis of the mucosa while the posterior gastrointestinal tract was not acidic and contained massive necrosis and sloughing of epithelial cells in the mucosa. Experimentally induced infections of vibriosis with water born exposure of fish to live bacteria were used to study the progress of disease. Both serotypes of V. anguillarum used in these studies were shown to enter fish by penetrating the descending intestine and rectum. Penetration of the skin is a second means by which V. anguillarum serotype II enters fish. Moribund fish in all studies suffered from hypoxia, possible accumulation of toxins (although not highly potent), loss of fluids in the posterior gastrointestinal tract, and dysfunction of various organs. Death of fish was apparently due to a combination of these ill effects. / Graduation date: 1979

The primary objective of this study was to identify and investigate the underlying basis for variation in the volume of exports of Canadian chum salmon during 1954-1975 period. A number of factors thought to be of importance in the determination of the volume of exports of chum salmon were hypothesized. These factors were: chum salmon price» the price of substitute commodities, the consumer income, population, general price level in importing countries, and fluctuations in exchange rates between Canadian currency and the currencies of the importing countries. The theoretical model was reformulated in terms of empirical models of demand for Canadian chum salmon in: West Germany, Sweden, and Italy. The empirical analysis focused upon the effects on annual export volume of changes in prices of Canadian chum salmon, changes in prices of salmon from other countries, and changes in consumer income in importing countries. The results suggest that: (1) in the case of Germany and Sweden, changes in prices of salmon from other countries and changes in consumer income, (2) in Italy, changes in Canadian chum salmon prices and changes in prices of salmon from other countries have been of principal importance in the determination of volume of exports of Canadian chum salmon. / Graduation date: 1979

Thesis (M.S.)--Oregon State University, 1977. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1972. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Eight scale characters of known hatchery and wild coho salmon (Oncorhynchus kisutch) were compared, and a linear discriminant function was used to determine if hatchery and wild adult coho salmon could be correctly identified by their scales. Eighty-two percent of the hatchery and 89% of the wild fish were correctly identified. Based on analysis of scales from adult salmon of unknown origin (hatchery or wild) and the estimated catch of hatchery coho (marked) taken by the Oregon sport fishery, concluded that 74.9% of the fish caught in the ocean from mid-June to mid-September 1977 had been released as smelts from hatcheries. Percentages of hatchery fish in the catch ranged from 85% near the mouth of the Columbia River to 61% at Winchester Bay on the southern Oregon coast. Fisheries on the south and central Oregon coast may have fished on higher percentages of wild coho salmon later in the season, probably because wild fish from coastal streams remained off of these ports while most fish destined for Columbia River hatcheries had already migrated northward. Scales from coho salmon were used to determine if location on the body from which they were taken would affect the values of five scale characters. Scales obtained from within a relatively small area above the lateral line between the dorsal and adipose fins differed widely in total radius, in radius of the freshwater zone, and in number of circuli in the freshwater zone. Scales taken farther above the lateral line had significantly lower values for all five characters observed. I conclude that substantial error can be introduced into interpretation of scale data if care is not taken to insure that scales from each fish come from precisely the same area of the body. A well chosen scrape sample yielded a result as satisfactory as that of a "preferred" or "key" scale. To investigate the relationship between streamflow and abundance of coho salmon, I correlated flow from several Oregon coastal rivers with catch of coho salmon from these rivers and with catch from the Oregon commercial troll fishery. I found a highly significant relationship between total streamflows during the freshwater residency of the fish for five Oregon coastal rivers combined and pounds of adult coho salmon caught by the Oregon commercial troll fishery from 1942 to 1962. There is also a significant relationship between total combined annual (January-December) flows for these rivers and a catch 2 years later. Conversely, I found a poor relationship between the lowest 60 consecutive days of summer flow and 2 two years later. I also found significant relationships between annual flows and catch in Tillamook Bay from 1934 to 1946. Only on the Siletz River from 1927 to 1940 do find a significant relationship between summer flows and catch. Higher flows during the freshwater stages of coho salmon probably provide more habitat and better conditions for growth as well as lessen susceptibility of fry and smelts to predation. I concluded that the relationships I found should probably not be used now to predict abundance of wild coho salmon because of (l) the unknown interaction between wild and hatchery fish, and (2) the preponderance of hatchery fish in the catch. / Graduation date: 1979