Postnesting migratory behavior of loggerhead sea turtles Caretta caretta from three Florida rookeries

摘要

ABSTRACT: We used satellite telemetry to study postnesting migrations of 42 loggerhead sea turtles Caretta caretta from 3 Florida rookeries. Postnesting migrations ended in neritic (200 m) waters of Florida, Alabama, Texas (USA), and of Mexico and the Bahamas. Most postnesting migrations were restricted to the continental shelf and were relatively direct. Migrations through oceanic areas (200 m) tended to be less direct, largely due to apparent influences of the Florida Current in the Atlantic and to looping travel paths (often along edges of mesoscale eddies of the Loop Current) in the Gulf of Mexico. The largest loggerheads tended to migrate to foraging grounds that were farthest from the nesting beach. Turtles spent more time near the surface (3 m) when migrating than they did during residency at foraging sites, and were likely swimming just below the surface. The substantial amount of time spent near the bottom in neritic areas and the looping travel paths in oceanic areas indicate that migrating loggerheads may have been foraging. We identified 4 migratory corridors. Two were on the continental shelf of the Florida Panhandle, 1 was along the northern coast of Cuba, and 1 was along the southeastern coast of Florida. Migrating loggerheads may be uniquely vulnerable to mortality factors because of where they travel and how they behave, particularly if they are concentrated in narrow (perhaps 10 km wide) migratory corridors. Characterizing the behavior and identifying the travel paths of loggerheads during postnesting migrations are necessary steps for implementing successful recovery efforts.