Post-nesting movements and feeding grounds of a resident East Pacific green turtle Chelonia mydas population from Costa Rica

Abstract

Satellite telemetry has helped reveal migratory movements of sea turtles. We attached satellite transmitters (MK10 Pat Tags) to 10 post-nesting East Pacific green turtles Che- lonia mydas from Nombre de Jesus, Costa Rica (in 2006, 2007 and 2009) to track their movements, identify their foraging grounds, and elucidate their foraging behavior. Location data were ana- lyzed by applying a switching state-space model to obtain daily position estimates and to differ- entiate between 2 behavioral modes (migrating and foraging). All post-nesting movements were along coastal routes ranging up to 1086 km from the nesting beach. Of the 10 turtles, 6 remained local residents of Costa Rica foraging in the Gulf of Papagayo (N = 2) and the Gulf of Santa Elena (N = 4). One individual moved southwards to the Gulf of Panama, and 3 other turtles migrated northwards to waters off the Gulf of Fonseca in northern Nicaragua, with one continuing its forag- ing movements northwards to coastal Guatemala. Home ranges during foraging varied widely among individuals, and the calculated size of feeding grounds ranged from 315 to 18 335 km 2 , the latter being the largest reported for this species. The fact that members of this nesting population inhabit coastal waters makes them vulnerable to human activities along the coasts of Central America. Our findings highlight the importance of Costa Rica and the coastal waters of Central America for the survival of the Endangered Costa Rican green turtles.