Food preferences and Hg distribution in Chelonia mydas assessed by stable isotopes.

Mercury (Hg) is a highly toxic pollutant that poses in risk several marine animals, including green turtles (Chelonia mydas). Green turtles are globally endangered sea turtle species that occurs in Brazilian coastal waters as a number of life stage classes (i.e., foraging juveniles and nesting adults). We assessed total Hg concentrations and isotopic signatures ((13)C and (15)N) in muscle, kidney, liver and scute of juvenile green turtles and their food items from two foraging grounds with different urban and industrial development. We found similar food preferences in specimens from both areas but variable Hg levels in tissues reflecting the influence of local Hg backgrounds in food items. Some juvenile green turtles from the highly industrialized foraging ground presented liver Hg levels among the highest ever reported for this species. Our results suggest that juvenile foraging green turtles are exposed to Hg burdens from locally anthropogenic activities in coastal areas.

Fibropapillomatosis in green turtles Chelonia mydas in Brazil: characteristics of tumors and virus.

Fibropapillomatosis (FP) is a benign neoplasia that affects physiological functions of sea turtles and may lead to death. High prevalence of FP in sea turtle populations has prompted several research groups to study the disease and the associated herpesvirus, chelonid herpesvirus 5 (ChHV5). The present study detected and quantified ChHV5 in 153 fibropapilloma samples collected from green turtles Chelonia mydas on the Brazilian coast between 2009 and 2010 to characterize the relationship between viral load and tumor characteristics. Of the tumor samples collected, 73 and 87% were positive for ChHV5 in conventional PCR and real-time PCR, respectively, and viral loads ranged between 1 and 118.62 copies cell⁻¹. Thirty-three percent of turtles were mildly, 28% were moderately and 39% were severely affected with FP. Skin samples were used as negative control. High viral loads correlated positively with increasing FP severity in turtles sampled on the Brazilian coast and with samples from turtles found dead in the states of São Paulo and Bahia. Six viral variants were detected in tumor samples, 4 of which were similar to the Atlantic phylogenetic group. Two variants were similar to the western Atlantic/eastern Caribbean phylogenetic group. Co-infection in turtles with more than one variant was observed in the states of São Paulo and Bahia.