Origin of Green Turtles, Chelonia mydas, at "Sleeping Rocks" off the Northeast Coast of Nicaragua

The largest foraging population of the Atlantic green turtle, Chelonia mydas, occurs in offshore waters of Caribbean Nicaragua. Green turtles are primarily herbivorous, and the extensive sea grass beds in Nicaraguan waters are utilized both by adults and juveniles. Based on tags recovered from adult females, at least two nesting populations contribute individuals to this feeding aggregate: Tortuguero, Costa Rica; and Aves Island, Venezuela. One goal of this study is to determine the origin for adult turtles off the northeastern coast of Nicaragua by utilizing mtDNA markers observed at eight Atlantic nesting colonies and one Mediterranean nesting colony. Stock information has immediate applications; wildlife managers need to know which nesting populations occur in Nicaragua's offshore waters to assess impact of the harvest. A second goal is to compare haplotype frequencies between male and female feeding cohorts. Because only females come ashore to nest (hence only one sex is tagged at the nesting colonies), male migratory behaviors are not well known. Genetic markers provide an opportunity to examine movements of both sexes and to test for possible differences in migratory behaviors.