Meeting Abstract

P3.13  Thursday, Jan. 6  The Growth and Molting of Blue Crabs (Callinectes sapidus) from the Tidal Freshwater James River WILLIAMS, L.E.; Virginia Commonwealth University williamsle@vcu.edu

The blue crab is an ecologically and economically important invertebrate to the Chesapeake Bay. The juvenile male blue crab moves into low salinity areas during warmer months to feed and grow by undergoing molting. The tributaries afford important habitat during this vulnerable life stage. In crustaceans, growth, molting and reproduction are all hormonally controlled and the juvenile molting crab may be the life stage that is most sensitive to low doses of chemicals that are found in the James River. Multiple chemical contaminants coexist in the James River, creating an environment ripe for interactions that could potentially result in synergistic effects on aquatic crustaceans. One emerging contaminant of concern is polybrominated diphenyl ether (PBDE), a flame retardant that is a known endocrine disrupting chemical and is found throughout marine sediments and biota. The commonly used herbicide atrazine may interact with PBDEs, potentially causing synergistic adverse effects at lower concentrations that, for each chemical individually, show no adverse effect. The first part of this research establishes growth and molting morphometrics for juvenile male crabs from the tidal freshwater reach of the James River, VA. Male crabs have been collected in this part of the river, ranging from carapace width of 20 mm to adult animals exceeding 100 mm. We collected male crabs less than 60 mm carapace width, returned them to the wet lab at VCU main campus and held them in a recirculating, filtered system at 22 C, and feeding crabs fish every other day. We measured increases in body mass and carapace width at molt, as well as time to molt and time between molt. At the molt, small crabs increase total body mass substantially, by as much as 100 percent or greater, similar to results reported in the literature.