Postnesting migration routes and fidelity to foraging sites among loggerhead turtles in the western North Atlantic

Abstract

Although the western North Atlantic hosts the largest nesting assemblage of loggerhead turtles (Caretta caretta) in the world, their fine-scale habitat use beyond the nesting beach and how it effects reproductive output is still poorly understood. To characterize internesting and postnesting habitats used by loggerheads in the region, we satellite tracked 32 individual mature female turtles from a nesting beach in the southeastern Gulf of Mexico from 2009 to 2016. Thirteen of these turtles were tagged and tracked for two or more nesting seasons to assess fidelity to internesting movements, migratory pathway, and foraging site. Internesting movements for all turtles occurred over the West Florida Shelf in relatively close proximity to the nesting beach. Migratory pathways along the continental shelf led to foraging areas in four distinct regions: the southeastern Gulf of Mexico (n = 16 turtles), northeastern Gulf of Mexico (n = 8), Bahama Banks (n = 7), and Campeche Bank (n = 1). Individual turtles exhibited high fidelity to foraging sites across seasons, and 22 of the 32 tracked turtles shared overlapping foraging area utilization with at least one other individual during the tracking period. Loggerheads foraging closest to the nesting beach in the southeastern Gulf of Mexico were generally smaller than those foraging in other regions. This work highlights the importance of the West Florida Shelf for eastern Gulf of Mexico sea turtle rookeries. Identifying and managing the multiple in-water habitats used within and between nesting seasons will help sustain loggerhead turtle population recovery and maintenance.