Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: [83]-91)

Little is known of trace metal concentrations and their possible role in the mortality of critically endangered Kemp??s ridley sea turtles (Lepidochelys kempii). Research described herein characterized concentrations of seven trace metals ?? Ag, Cd, Cr, Cu, Hg, Pb and Zn ?? in the blood and carapace tissue of captive Kemp??s ridleys for use in assessing levels of these metals in wild counterparts. Concentrations of same trace metals were characterized in post-pelagic through adult life stages of 127 wild Kemp??s ridleys captured from the Gulf of Mexico and southeast Atlantic during 2000 to 2002. Blood, carapace, liver, kidney, and muscle tissues from live and/or stranded Kemp??s ridleys were analyzed for the aforementioned trace metals via graphite furnace atomic absorption spectrophotometer and cold vapor atomic fluorescence techniques conducted under class-100 clean laboratory conditions. Similar trace metal assessments were conducted on blue crab (Callinectes sapidus) prey to determine the role of food as a possible uptake pathway in Kemp??s ridleys. Overall, trace metal levels in live, captive as well as wild ridleys were higher in carapace tissue than in blood. Carapace concentrations of Ag, Cr and Hg in Kemp??s ridleys across all post-pelagic life stages increased with increasing straight carapace length (SCL). Carapace tissue of wild ridleys exhibited higher Cr, Hg, and Pb levels than their blue crab prey, regardless of study area; whereas, crabs yielded higher Ag and Cu concentrations. Dead stranded ridleys yielded higher Ag, Cr, Hg, Pb, Zn levels in carapace tissue, whereas, their liver exhibited higher Cd and Cu levels. This finding suggests carapace tissue could serve as a suitable surrogate sample source for internal organs/tissues when monitoring exposure of live Kemp??s ridleys to certain metals. The fact that larger, stranded ridleys exhibited higher Ag, Cd, Hg, Pb and Zn levels than did their smaller, live analogs from Texas and Louisiana implies that these older ridleys had increased opportunities to accumulate higher metal concentrations in their carapace tissue than did their younger conspecifics. This trend suggests that carapace tissue has the potential to accumulate trace metals while blood-borne concentrations reflect only recent exposure to trace metals.

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 129-131). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 107-118). Also available via the Internet.

Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Member: Roberts, Philip; Committee Member: Sturm, Terry; Committee Member: weissburg, marc; Committee Member: yoda, minami. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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.

Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 40-42)

Master of Science

Hypoxia or dissolved oxygen concentrations < 2 mg/L is a problem in estuaries worldwide. In Lake Pontchartrain, a 250 km2 de-faunated zone exists as a result of salinity stratification and episodic hypoxia. Mature common rangia clams (Rangia cuneata) are not found within this zone. Blue crabs (Callinectes sapidus) are important estuarine predators and may move in and out of the hypoxic zone to feed on hypoxia-stressed rangia clams. To test the effects of hypoxia on predation, rangia clams were exposed experimentally to severe hypoxic conditions (< 0.75 mg/l) for 72-hours and then presented to blue crabs. One hypoxic and one normoxic clam were added to each aquarium containing a blue crab for each trial, and crab feeding choices were observed and recorded. I found prey choice varied among crabs, but in general, the experimental data demonstrates that crabs chose to feed on hypoxia-stressed clams over clams kept under normoxic conditions.