Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on June 07, 2010). Includes bibliographical references (p. [53]-56).

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

xi, 91 leaves : ill. Typescript Thesis (M.S.)--University of Oregon Includes vita and abstract Bibliography: leaves 87-91 Another copy on microfilm is located in Archives University of Oregon theses, Dept. of Biology, M.S., 1982

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

No description available.

This study was initiated to assess the biological, ecological and sociological aspects of the blue crab, Callinectes sapidus, fishery associated with the Pascagoula River Estuary in southern Mississippi. Household surveys were conducted in the cities of Moss Point and Pascagoula, Mississippi, September 2010 to September 2011, to identify, describe and classify subsistence fishing activities associated with the estuary. A stock assessment of blue crab was conducted to determine how biological and environmental variability affect the people engaged in this subsistence fishery. The study revealed two types of subsistence fishing occurring in the Moss Point/Pascagoula area. The first type involves fishing as a livelihood strategy based on economic dependence, and the second type involves fishing as a lifestyle choice based on economic independence. Both are based on customary and traditional patterns of local resource use and consumption and maintained by reciprocal kinship-based social networks. The blue crab fishery in the Pascagoula River Estuary was highly variable and exhibited strong seasonal and spatial patterns in distribution and abundance. Subsistence fishers in the region have developed strategies to cope with this biological and environmental variability. These region-specific strategies include but are not limited to: fishing using multiple gears simultaneously (rod and reel and crab nets), freezing fish, relying on other natural resources including agriculture and wildlife, and generalized reciprocity.