Defense Date


Document Type


Degree Name

Master of Science


Environmental Studies

First Advisor

Peter L. deFur

Second Advisor

Michael L. Fine

Third Advisor

Jennifer K. Stewart


Juvenile male blue crabs move into the tidal, freshwater James River during warmer months to feed and grow by undergoing molting. In crustaceans, growth and molting are hormonally controlled. The physiological effects of a multiple-stressor environment are determined by comparing the blue crab’s oxygen uptake after exposure to pure sand, James River sediment, or endosulfan-spiked sand. The effect of multiple stressors on molting is measured by the activity level of N-acetyl-ß-glucosaminidase (NAG), an enzyme in epidermal tissue important to molting. The oxygen uptake was decreased by exposure to James River sediment but not for exposure to endosulfan for seven days. Exposure to James River sediments over two days caused a similar suppression of epidermal NAG activity as exposure to endosulfan. These results indicate that the blue crab’s exposure to James River sediments and moderate hypoxia has the potential to cause short-term effects on physiology and long-term effects on growth.


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Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

December 2012