Meeting Abstract

12.5  Thursday, Jan. 3  Effects of Hurricane Rita on Alligators in Southwest Louisiana LANCE, Valentine A.*; ELSEY, Ruth M.; TROSCLAIR III, Phillip; MERCHANT, Mark; San Diego State University; Louisiana Department of Wildlife and Fisheries; Louisiana Department of Wildlife and Fisheries; McNease State Univeristy lvalenti@sunstroke.sdsu.edu

Hurricane Rita produced an enormous tidal surge when it came ashore directly south of Lake Charles, Louisiana in September 2005. Many thousands of acres of freshwater marsh were inundated with up to four meters of full strength seawater. A large number of alligators were found dead, and one of us (M.M.) was able to collect blood samples from 11 alligators stranded on a beach on the Gulf of Mexico in October 2005. The biologists at the Rockefeller Wildlife Refuge were able to collect an additional 201 blood samples from February to August 2006. Alligators are intolerant of salt water and will move to avoid it, but under these conditions there were no areas of fresh water in the area. The high salt concentration in the available water caused extreme dehydration in the resident population. This physiological stress was exacerbated by a lack of rain. High salinity conditions continued until June, July and August 2006 when substantial rainfall was recorded and the alligators were able to re-establish physiological homeostasis. Corticosterone, plasma osmolality and plasma electrolytes were measured in all of the samples. Plasma corticosterone was highly elevated in alligators that exhibited indices of dehydration (high plasma electrolytes and osmolality) and inanition, and was low in alligators that were sampled in areas of lower salinity. These results validate laboratory experiments with alligators in which osmotic stress resulted in high plasma corticosterone.