ABSTRACT:The health status of 83 loggerhead sea turtles (Caretta caretta; 39 foraging, 31 nesting, and 13 stranded turtles) was analyzed using physical examinations, hematology, plasma biochemistry, plasma protein electrophoresis, and toxicologic parameters. Significant differences were noted in a number of health parameters between turtles exhibiting each of these behaviors. On physical examinations, stranded turtles had the highest prevalence of heavy carapace epibiont loads, miscellaneous abnormalities, emaciation, and weakness. Differences in hematologic values included a lower packed cell volume, higher number of lymphocytes, and lower number of monocytes in stranded turtles; lower white blood cell counts in foraging turtles; and significant differences in total solid values among turtles exhibiting all behaviors with the lowest values in stranded turtles and the highest values in nesting turtles. Differences in plasma biochemistry values included the highest uric acid, creatine kinase, and CO 2 values in stranded turtles; the highest glucose and potassium values in foraging turtles; and the highest cholesterol and triglyceride values, and lowest alanine aminotransferase, in nesting turtles. Differences in total protein, albumin, and globulin were found using plasma biochemistry values, with lowest values in stranded turtles and highest values in nesting females, whereas differences in blood urea nitrogen between turtles included the lowest values in nesting turtles and the highest in foraging turtles. Plasma organochlorine and polychlorinated biphenyl levels were below their limits of quantification in the 39 foraging, 11 nesting, and three stranded turtles tested. A statistically significant difference was noted in the level of whole blood mercury between the 23 foraging and 12 nesting turtles tested. There was no difference in arsenic or lead levels between turtles exhibiting any of the three behaviors. Although a few limitations exist with the present study and include unknown ambient temperatures, turtle handling times that varied from 15 min to 53 min per turtle, and the use of a different laboratory for processing complete blood counts and plasma biochemistries in stranded versus foraging and nesting turtles, we provide baseline blood values for two cohorts (foraging and nesting) of loggerhead sea turtles on the coast of Georgia. Additionally, we demonstrate significant differences in clinical findings and blood parameters between foraging, nesting, and stranded loggerhead turtles in the region.

During summer of 2001, venous blood gases were determined in loggerhead sea turtles (Caretta caretta) captured by trawl (nϭ16) in coastal waters of South Carolina and Georgia (USA) as part of a sea turtle census program and captured in pound nets (nϭ6) in coastal North Carolina (USA) during a study of sea turtle population biology. Trawls were towed for 30 min, so turtles captured were forcibly submerged for Յ30 min. Pound nets are passive gear in which fish and sea turtles are funneled into a concentrated area and removed periodically. Sea turtles in pound nets are free to surface and to feed at will. Blood was obtained from the dorsal cervical sinus as quickly as possible after landing on the boat (range 2-10 min trawl, 1-2 min pound net) and at 30 min after landing just prior to release. Blood gases including pH, partial pressures of O 2 and CO 2 (pO 2 , pCO 2) , and lactate were measured within 10 min. Instrument measurements for pH, pO 2 , and pCO 2 made at 37 C were corrected to cloacal temperature and HCO 3 Ϫ was calculated from temperature-corrected pH and pCO 2 . Venous blood pH and bicarbonate were higher, and pO 2 and lactate were lower from pound net-captured turtles compared to trawl captured turtles at the initial sampling time. In pound net turtles, pH and bicarbonate declined and lactate increased during 30 min on deck. In trawled sea turtles, venous blood pH increased and pCO 2 and pO 2 decreased during the 30 min on deck. Both capture systems caused perturbations in blood gas, acid-base, and lactate status, though alterations were greater in trawl captured turtles.

BackgroundMercury is a pervasive environmental pollutant whose toxic effects have not been studied in sea turtles in spite of their threatened status and evidence of immunosuppression in diseased populations.ObjectivesIn the present study we investigate mercury toxicity in loggerhead sea turtles (Caretta caretta) by examining trends between blood mercury concentrations and various health parameters.MethodsBlood was collected from free-ranging turtles, and correlations between blood mercury concentrations and plasma chemistries, complete blood counts, lysozyme, and lymphocyte proliferation were examined. Lymphocytes were also harvested from free-ranging turtles and exposed in vitro to methylmercury to assess proliferative responses.ResultsBlood mercury concentrations were positively correlated with hematocrit and creatine phosphokinase activity, and negatively correlated with lymphocyte cell counts and aspartate amino-transferase. Ex vivo negative correlations between blood mercury concentrations and B-cell proliferation were observed in 2001 and 2003 under optimal assay conditions. In vitro exposure of peripheral blood leukocytes to methylmercury resulted in suppression of proliferative responses for B cells (0.1 μg/g and 0.35 μg/g) and T cells (0.7 μg/g).ConclusionsThe positive correlation between blood mercury concentration and hematocrit reflects the higher affinity of mercury species for erythrocytes than plasma, and demonstrates the importance of measuring hematocrit when analyzing whole blood for mercury. In vitro immunosuppression occurred at methylmercury concentrations that correspond to approximately 5% of the individuals captured in the wild. This observation and the negative correlation found ex vivo between mercury and lymphocyte numbers and mercury and B-cell proliferative responses suggests that subtle negative impacts of mercury on sea turtle immune function are possible at concentrations observed in the wild.

Values reported here will be useful for evaluating the health status of bonnetheads in wild and captive research conditions and in exhibits.