COMPARISON OF MERCURY BURDENS IN CHRONICALLY DEBILITATED AND HEALTHY LOGGERHEAD SEA TURTLES (CARETTA CARETTA)

An increasing in the incidence of debilitated loggerhead sea turtle (Caretta caretta) strandings in the southeastern United States has been observed in recent years. These turtles are characterized by emacation and heavy burdens of external and internal parasites, and bacterial infections, but the underlyng cause of their condition is unknown. To investigate further the causes of these strandings, a health assessment was performed on stranded, debilitated loggerhead turtles, and contimanant concentrations in various tissues were compared to those from healthy turtles. This portion of the study investigated the potential role of mercury (Hg) toxicity in the debilitated conditoin described above. Hematocrit, total protein, albumin, globuli, glucose, calcium, lymphocyte counts, heterophil:lymphocyte ratios, aspartate aminotransferase, uric acid, sodium, and chloride were altered in debilitated loggerrheads relative to healthy animals. However, none of the aforementioned healthy indicators correlated with Hg concentrations in either red blood cells (RBCs) or plasma. The Hg concentration in RBCs was 129 +/- 72 (mean +/- standard deviation) times higher than in plasma, causing a significant dilution of Hg in whole blood due to extreme anemia. Mercury concentrations in RBCs (73.7 +/- 21.2 ng/g) and scutes (455 +/- 57 ng/g) from debilitate dturtles were similar to or lower than those reported fo rhealthy animals, indicating no elevation in Hg exposure before and during the pgoression of this condition. These findings suggest that Hg toxicity does not play a role in the debilitated loggerhead condition observed in the southeastern United States.