Thesis (M.A.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 42-46). Also available via Humboldt Digital Scholar.

Thesis (Ph.D.)--Oregon, Dept. of Biology Vita Bibliography: l. 135-144

Thesis (M.S.)--Oregon, Dept. of Biology Vita Bibliography: l. 54-59

xiii, 233 leaves : ill. ; 29 cm, Typescript. (Another copy on microfilm is located in Archives) Thesis (Ph.D.)--University of Oregon Includes vita and abstract Bibliography: leaves 220-233 University of Oregon theses, Dept. of Biology, Ph.D., 1978

Regulation of chloride, sodium, potassium, calcium, and magnesium ions was determined for hypo- and hypersaline conditions in the crab, Cancer magister, from an estuarine environment. Animals from both summer and winter were examined. Chloride regulation in the blood was hypertonic in dilute salinities and hypotonic in concentrated salinities, with summer animals maintaining a greater gradient in the former and winter animals a greater gradient in the latter. Sodium in the blood is regulated hypertonically in all experimental salinities, with summer animals maintaining a greater gradient. Blood potassium is regulated hypertonically in dilute salinities, approaching isotonicity in hypersaline media. Summer animals maintain a greater gradient of potassium concentration. Blood calcium is regulated hypertonically in all experimental salinities, with summer animals maintaining a greater gradient in dilute salinities and winter animals a greater gradient in concentrated salinities. Magnesium is regulated at a pronounced hypotonic level in the blood over the entire experimental salinity range, with winter animals maintaining the greater gradient. Major changes in the adaptation of blood ionic concentrations occur within a few hours of exposure to the experimental salinities, with half of the final equilibrated concentration values attained by twelve hours. Animal weight was found to bear no significant relationship to the ionic regulatory activity observed. Renal involvement in regulation has been shown for all the ions, with the production of a urine hypertonic to the blood for chloride and magnesium, and a urine hypotonic to the blood for sodium, potassium, and calcium. Renal regulation was greater in winter animals for chloride, and greater in summer animals for sodium and potassium. Ionic regulation by the gills of summer and winter animals was investigated by potential difference measurements, and was suggested to occur for all ions. Chloride may have been regulated by the absorption from dilute media and excretion into concentrated media. Sodium may have been regulated by secretion into dilute media. The involvement of the gill in potassium, calcium, and magnesium regulation was implicated. / Science, Faculty of / Zoology, Department of / Graduate

The biological half-life of inorganic mercury in the Dungeness crab, Cancer magister Dana, was determined experimentally to be about 25 days. Crabs were exposed to mercury solutions, sacrificed after varying periods of time, and mercury determinations of whole body homogenates made with an atomic absorption spectrophotometer. The simple and widely used negative exponential equation for calculating biological half-life was not entirely adequate for describing the mercury elimination process. A better description was obtained using a nonlinear least-squares fit of an equation describing elimination at different speeds from two types of tissues. A further model allowed for recycling of mercury that was eliminated, and gave marginally better descriptions in some cases. / Science, Faculty of / Zoology, Department of / Graduate

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 93-101). Description: xi, 101 leaves : ill. ; 29 cm.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 54-60). Description: xi, 60 leaves : ill. ; 29 cm.

The Dungeness crab fishery is the most economically important on the West Coast; however, it has experienced dramatic fluctuations in annual catch. Previous research has shown the annual catch of megalopae is correlated with the commercial catch. The catch of megalopae is correlated with the phase of the Pacific Decadal Oscillation (PDO), the day of the year of the spring transition and the amount of upwelling following the spring transition. Further, the daily catch of megalopae is correlated with the internal tide. We developed individual based models of Dungeness crab dispersal, which we validated with results from a light trap. We demonstrated that the retention of larvae in the California Current is enhanced during negative phase PDOs. Further, we suggest that larvae migrate to or almost to the bottom each day. Specifically, megalopae exhibit a twilight vertical migration off of the continental shelf and remain in the neuston on the continental shelf. This concentrates megalopae at the continental shelf break. We also observed megalopae in situ and demonstrated that they swim in the neuston with the surface current at speeds of ~ 10 cm s-1. Using these results and data from a mooring, we demonstrated that this behavior would increase the distance internal waves would transport larvae. We analyzed mooring data and suggest that catch of megalopae is greater when the thermocline is deep and weak and there is less horizontal shear. We hypothesize this allows internal waves to remain coherent longer on the continental shelf. We show that the spring transition coincides with a shallowing of the thermocline, which would ultimately lead to the development of internal waves of depression rather than elevation. We hypothesize that the change in surface flow, based on whether the wave is one of elevation or depression, explains why most megalopae are caught following the spring transition. In general, these findings help us better understand the dispersal of Dungeness crabs. We suggest the dispersal patterns support Michael Sinclair’s member vagrant hypothesis. Further, we suggest these findings apply to many of the continental shelf species in the California Current. This dissertation includes both published and unpublished co-authored materials.

Graduation date: 1968