Multidirectional migrations from a major nesting area in Turkey support the widespread distribution of foraging sites for loggerhead turtles in the Mediterranean

Abstract

Satellite tracking studies have identified some of the migratory corridors and foraging sites of Mediterranean loggerhead sea turtle (Caretta caretta) rookeries over the past few decades. However, due to a lack of information for breeding rookeries in Libya and Turkey, our understanding of the distribution and connectivity of adult loggerheads is limited. We satellite-tracked 17 female loggerhead turtles breeding in one of the main nesting areas in Turkey to identify (1) migratory pathways, and (2) their foraging areas. Females were tracked for 96-657 d (mean: 271 d), and followed 3 general migratory directions (southeast, southwest and northwest/west). While migrating, individuals alternated oceanic and neritic movements, generally travelling significantly slower when in neritic waters (average speed reduction: 20%). Five turtles stopped between 1 to 3 times in stopover sites for <6 d before resuming their migration. While 1 turtle resided in oceanic foraging areas, the remaining 16 loggerheads settled in 12 distinct neritic foraging grounds; 2 turtles shared one site and 4 turtles shared another site. The identified foraging grounds were widely distributed across the Eastern and Central basin, in locations known to be frequented by loggerhead turtles from other rookeries. The present findings reveal links between foraging areas and one of the main breeding sites in Turkey, providing useful information for species conservation.