Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 228-246).

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 61-65). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2000. / Typescript (photocopy). Includes bibliographical references (leaves 100-102). Also available on the World Wide Web.

Part of the general investigation being conducted by the Fisheries Research Board of Canada into the condition of the Pacific coast otter trawl fishery deals with the length and age analysis of the species of fish caught. The age of one of these species, the lemon sole, Parophrys vetulus GIrard has been determined through a study of the otoliths or ear-stones. In general the older fisheries and those closest to large Canadian and American markets produce the youngest and the smallest fish. Soles of four and five years of age predominate in the catches from the Strait of Georgia and from the west coast of Vancouver Island. The comparatively recent fisheries of Queen Charlotte Sound and Hecate Strait show a predominance of six and seven year old fish. The male lemon sole reaches an age of ten years and a length of 400mm., while the female reaches twelve or thirteen years of age and grows to a length of over 500mm. The female sole, between four and eight years of age grows approximately 11 mm. more per year than the male. The fish in the Strait of Georgia and in northern Hecate Strait have a slightly greater growth rate than those on the west coast of Vancouver Island and in Queen Charlotte Sound. Marked differences in total annual mortality rates have been shown. In the Strait of Georgia and on the west coast of Vancouver Island the rate is between 60% and 70%. In Queen Charlotte Sound the rate is 52%, and in northern Hecate Strait it is between 30% and 40%. The relative recency of the northern Hecate Strait fishery has raised the suggestion that the total mortality rates of 30% in female fish and 39% in male fish approach the natural mortality rate. Dominance of the 1939 year class has been observed in the s study of fish taken during 1944, 1945 and 1946 in northern Hecate Strait. In the last year another strong year class, that of 1942, made its appearance. The relative lack of success in the brood years of 1940 and 1941 was the factor responsible for the absence of small fish in the catches during the fishing seasons of 1944 and 1945. / Science, Faculty of / Zoology, Department of / Graduate

The winter fishery for lemon sole in the gulf of Georgia depends on populations spawning in Baynes sound and Boat harbour from January to March. The peak period in 1946 was from January 24 to February 23 in Baynes sound and 10 days earlier in Boat harbour. Although some spawning took place throughout the whole of both regions, with the exception of Porlier pass, spawning was more intense in certain areas of each region. Minimum estimates of fishing intensities of 42% and 26.3% for the Baynes sound and Boat harbour regions respectively appear too heavy to maintain the fishery at its present level. During the 1947 fishing season Baynes sound was largely closed to trawling; in Boat harbour the percentage tag recovery was 6.3% as compared to 18.8% for the same period in 1946. These recoveries indicated an average annual increase in length of 7.3% or in weight of 21.9%. Lemon sole spawning in Baynes sound dispersed to parts of the gulf north of Nanoose bay, while those spawning in Boat harbour dispersed southward as far as the American boundary. Although these two populations do not mix to an appreciable extent, their composition is very similar except for a larger number of immature and small mature fish in Baynes sound. The Porlier pass population, consisting of two-thirds immature fish differed markedly. An estimate of the amount of population change on the spawning grounds was made by comparing the variations in tag returns per period calculated on the basis of a constant number of tagged fish available and a constant weight of fish caught each period. Stomach analysis showed that lemon sole do not feed actively during the winter and that fully matured fish feed less actively than- immature or spent individuals. Worms, clams, and brittlestars formed the principal foods. / Science, Faculty of / Zoology, Department of / Graduate

ix, 77 leaves : ill. ; 29 cm Notes Typescript Thesis (M.S.)--University of Oregon, 1986 Includes vita and abstract Bibliography: leaves 73-77 Another copy on microfilm is located in Archives

This thesis focuses upon whether stressful aspects of an organism's environment are reflected by that organism's shape. It presents an application of the powerful thin-plate spline and relative warp methods from morphometric analysis to demonstrate the overall utility of morphometrics in detecting environmental stress in an estuarine flatfish, the English sole or Pleuronectes vetulus. Juvenile English sole were captured from the Yaquina Bay, Oregon, photographed using a digital camera, and then held without food in the laboratory for periods of 7 to 24 days. Landmarks on the outline of the ventral surface of the body were digitized from the images. The mean position of the landmarks for freshly caught sole was used to compute a reference specimen. The thin-plate spline method was then applied to quantify the intraindividual shape variation due to lab-induced environmental stressors for all fish. Relative warp analysis of the resulting landmark data yielded relative warp scores for each individual fish, and was analogous to a principal component analysis. Analysis of covariance of the relative warp (principal component) scores showed that fish held without food acquire different shape characteristics in comparison with freshly caught fish, and that these shape differences reflect captivity and food deprivation effects. A discriminant function analysis using the data allows clear differentiation of stressed and non-stressed fish. The underlying goal of this research was to examine the conceptual and methodological aspects of morphometrics relevant to its future potential use as a measure of developmental precision and environmental condition. The technique may have applicability for detecting environmental stress in natural populations of estuarine fish. / Graduation date: 2003

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 57-62). Also available on the World Wide Web.

The pesticide carbaryl is applied annually to tidelands in Willapa Bay and Grays Harbor, WA to control populations of burrowing shrimp which modify sediments making the habitat unsuitable for oyster culture. Fish trapped on sprayed mudflats are often killed, but little is known about effects on fish present in subtidal channels or migrating over treated mudflats with a flood tide. The purpose of this work was to determine the effect of estuarine carbaryl applications on fish present in these areas. Field studies with caged juvenile English sole (Pleuronectes vetulus) indicated that brain acetylcholinesterase (AChE) activity is decreased following carbaryl application. Mean brain AChE inhibition was 26% in fish placed on treated mudflats and 24% in fish placed subtidally. Maximum individual values approached 50%. Maximum carbaryl water concentration measured by HPLC was 1.2 ug/ml at the cage sites. Sediment concentrations on treated mudflats were as high as 2300 ug/g OC 24 hrs post application. The concentration of carbaryl in invertebrates collected from treated mudflats has been measured as high as 76 ug/g, and English sole likely ingest these contaminated prey in the field. Laboratory studies conducted to evaluate the effect of such an oral exposure indicated that brain AChE activity is decreased with the ingestion of as little as 1% body weight of food pellets spiked to field concentrations. AChE inhibition exceeding 25% is predicted in wild fish based on the ingestion of average quantities of food (5% body weight) at average measured concentrations (30 ug/g). Limited recovery occurs 24 hrs after exposure indicating effects can be compounded with further ingestion. This oral exposure coupled with the effect measured in caged fish suggests AChE inhibitions exceeding 50% are possible assuming the effects are additive. The significance of this decrease in AChE activity was then evaluated in terms of two ecologically important endpoints. First, the effect of carbaryl on the ability of English sole to bury in sediments was determined Results indicate this behavior is affected by carbaryl in a dose-dependent manner with fish not burying at higher concentrations. A regression model indicated that 50-60% brain AChE inhibition is a threshold value below which burying decreased sharply. This is within the range of estimated field exposures. Recovery of burying behavior occurs shortly after the removal of the exposure with all exposed fish in the present study recovering the ability to bury in sediments within 24 hrs. Mean brain AChE inhibition at the time of recovery was 60%. The effect of carbaryl on the English sole nonspecific immune response was also evaluated. Head kidney phagocytes were isolated from English sole and exposed to carbaryl in vitro. Phagocytosis was then evaluated based on the percentage of cells ingesting heat killed yeast. The percentage of phagocytic cells decreased at doses of 10 and 100 ug/ml. These concentrations are likely higher than can be attained during an in vivo exposure. Effects on this immune response are thus unlikely in field exposed English sole. / Graduation date: 1999

Population abundances of English sole within the San Francisco Bay from 1973 to 1981 showed a significant positive correlation with Delta outflows, and a significant negative correlation with salinity. Temperature in the bay and ocean upwelling showed no correlation with English sole abundance in the Bay. Because of the positive correlation between the abundance of English sole in the South San Francisco Bay and Delta outflow, this study suggests that any factor resulting in a reduction in outflow may reduce the abundance of English sole in the sample area.