Latitudinal cline in the foraging dichotomy of loggerhead sea turtles reveals the importance of East China Sea for priority conservation

Abstract Aim Quantifying the importance of habitat areas for conservation highly migratory marine species with complex life histories can be challenging. For example loggerhead turtles ( Caretta caretta ) nesting in Japan forage both oceanically and neritically after their reproductive period. Here, we aimed to quantify proportions using these two contrasting habitats (foraging dichotomy) suggest priority areas. Location North Pacific Ocean. Methods We examined occurrence foraging dichotomy at three sites (Ishigaki, Okinoerabu Islands Ichinomiya) based on stable isotope analysis egg yolks 82 satellite tracking post‐nesting migration 12 turtles. Moreover, used data other from previous studies (Yakushima Island, Minabe Omaezaki). Results Two neritic grounds (East China Sea coastal area Japanese archipelago), an oceanic ground (North Ocean) were identified. found a latitudinal cline respect dichotomy; >84% females southern (Ishigaki Islands), 73% middle Island Minabe) <46% northern (Omaezaki foragers; proportion foragers increased sites. Based annual number nests entire region Japan, dichotomy, estimated that 70% 9% utilize East archipelago, respectively, 22% Main conclusions The represents critical populations endangered sea Our findings emphasize need international management ensure protection.