Satellite telemetry reveals hot spot for conservation of East Pacific green turtles (Chelonia mydas) during internesting in Costa Rica

GABRIELA S. BLANCO; STEPHEN J. MORREALE; JEFFREY A. SEMINOFF; FRANK V. PALADINO; JAMES R. SPOTILA

Hobart, Tasmania AU

Simposio; Fourth International Science Symposium on Bio-logging; 2011

We attached tether satellite transmitters (Mk 10 PAT, Wildlife Computers) to 13 East Pacific green turtles nesting on Nombre de Jesus and Zapotillal beaches to identify movements and dive behavior and to determine high use internesting areas in need of protection in northwestern Costa Rica. A fixed Kernel density analysis showed that high-use areas during internesting periods were close to the nesting beaches and 25, 50, 75 and 95% UD polygons included 1.57, 4.5, 9.4 and 53.9 km2 respectively. Turtles performed short dives (2-10 min) mainly in the first 10 m of the water column U-dives were shallow (3-5 m) and their modal duration ranged from 8 to 23 min. Strong diel patterns occurred in diving behavior during internesting with a significantly larger amount of time at the surface during the night. The proportion of U-dives was significantly negatively correlated with surface time at night suggesting the turtles were floating at the surface as a resting strategy. The combination of movement and behavioral data indicated that the turtles were staying near the nesting beach during the interesting period. The depths of dives and depth of water in the area indicated that the turtles swam to the bottom during u-dives in the daytime. At night they rested at the surface. This high concentration of turtles, the presence of males, mating near the beach and extensive use of the area by resting turtles indicated that this small area was of great importance for East Pacific green turtles and a hot spot for conservation of this population.