Boldness–exploration behavioral syndrome in wild sub-adult green sea turtles caught at Oita, Japan

Abstract

Boldness and exploration behaviors form a behavioral syndrome in dispersive species. Although green sea turtles are highly migratory and are often captured in coastal set nets of commercial fisheries in Japan, their personality and behavioral syndromes are not well understood. In this study of wild sub-adult green sea turtles (Chelonia mydas), we first confirmed personality consistency over time using fearful and novel stimuli (boldness, r = 0.63, P < 0.01; exploration, r = 0.41, P < 0.05). Secondly, we investigated the relationship between boldness and exploration behaviors to identify behavioral syndrome. The behavioral syndrome was observed in half of them (N = 11, r = 0.77, P < 0.01), however, was not observed in the other contrasting 11 turtles (N = 11, P = 0.9). Thirdly, we assessed behavioral plasticity by monitoring the adjustments of feeding behaviors in risky and safe scenarios using fearful stimulus. Turtles without behavioral syndrome showed a high plasticity of feeding behavior and adjusted their behaviors depending on the situation (P < 0.01). However, turtles with behavioral syndrome showed limited behavioral plasticity and did not adjust their behavior (P = 0.9). Finally, we estimated natal origins of test individuals. Despite having similar genetic origins, Ogasawara (mean = 84.5 % ± 11.8 %) and having been caught in the same area, turtles were categorized into two groups with/without behavioral syndrome. This difference of behavioral syndrome and plasticity might be caused by different habitat experiences during migration and their habitat.