Prey Species And Foraging Behaviour Of Indo-Pacific Bottlenose Dolphins (Tursiops Aduncus) Around Mikura Island In Japan

This study aimed to assess the prey species and foraging behaviour of Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Mikura Island, a small oceanic island similar to 200 km south of Tokyo, Japan, using underwater observations and stomach content analysis of eight individuals to determine the feeding ecology of this population. Our results suggest that T. aduncus feed on various species and exhibit concentrated foraging behaviour at night. We recorded 11 fish species, seven cephalopod species, and one crustacean species as prey, as well as 10 fish species and one crustacean species as potential prey. Our underwater observations revealed that females performed foraging behaviour during daytime significantly more frequently than males. This is the first study using underwater observations to assess foraging and prey species of small cetaceans in Japan.