W9 PM Residual Oil and its Effects
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in 339-340

(CUL-1117-742070) Behavioral effects on the salt marsh fiddler crab, Uca pugnax, chronically exposed to petroleum hydrocarbons.

Culbertson, J¹, Valiela, I¹, Peacock, E², Reddy, C², Carter, A³, ¹ Boston University Marine Program/Marine Biological Laboratory, Woods Hole, MA, United States² Woods Hole Oceanographic Institution, Woods Hole, MA, United States³ East Tennessee State University, Johnson City, TN, United States

ABSTRACT- Over thirty years after the barge Florida spilled approximately 700,000 L of No. 2 fuel there is still substantial undegraded residue at a depth of 10-14 cm. within salt marsh sediments of Wild Harbor, MA. Although the salt marsh vegetation seems to be recovered, fiddler crabs, Uca pugnax, which burrow into the sediments, could be exposed to the petroleum residue. To test for possible effects of exposure to the buried oil, we assessed feeding rates of populations of U. pugnax from Wild Harbor and a control site, Great Sippewissett marsh. Crabs from both marshes were exposed to contaminated sediments for two weeks, and we then measured fecal pellet production (as a proxy for feeding rate). Fecal pellet production was significantly lower with exposure to oiled sediments. Another indication of the response of crabs to the oil was that casts of fiddler crab burrows indicated significantly abnormal burrow construction in oiled areas versus non-oiled areas. Burrows from Wild Harbor were, on average, 45% shorter in length then those from Great Sippewissett, and often turned laterally at depths greater than 10 cm., sometimes even turning upwards. Many years after the spill, the residual oil still appears to have measurable effects on fiddler crab populations.

Key words: fiddler crabs, Wild Harbor, oil spills, petroleum hydrocarbons