A man says he is lucky to be alive after being attacked by a “sexually frustrated” dolphin which experts believe is responsible for terrorising a Japanese town all summer.

Takuma Goto had been swimming off the town of Tsuruga in central Japan with a friend earlier this summer when they were attacked by a lone dolphin.

Experts believe a single dolphin, which may be sexually frustrated, could be responsible for at least 15 attacks on swimmers in Fukui this summer, up from five incidents last summer and one in 2022.

Dolphin attacks on humans are generally considered rare, given that they do not see us prey, which initially gave Mr Goto a false sense of security.

He and a friend had been swimming at Crystal Beach before going around 20 metres offshore when the dolphin attacked, first targeting his friend.

Alarmed at his friend’s cries, Mr Goto turned to see what was happening as the dolphin’s head breached the surface.

“I knew it was not a shark, but it came straight at me,” he said, adding that he did nothing to attract or antagonise the dolphin, but that it nonetheless began a sustained assault.