Just when you thought it was safe to get back into the water! Man says he is lucky to be alive after being attacked by sexually frustrated dolphin

A who was attacked by a sexually frustrated dolphin has said he is lucky to be alive.

Takuma Goto was swimming with a friend near the town of Tsuruga in central Japan when they encountered a single dolphin, believed to be responsible for as many as 15 attacks over the summer.

The pair had swam 20 metres offshore from Crystal Beach when the mammal attacked them.

Dolphins are not typically thought to be a threat to humans, which they dont usually see as prey.

But signs had been put up by the local authority warning swimmers of attacks from dolphins, the Telegraph reported.

A man has said he is lucky to be alive after he was attacked by a bottlenose dolphin off the coast of Japan 

Takuma Goto was rescued by nearby surfers after he encountered the lone dolphin while swimming of the coast of central Japan

Swimmers were warned of possible dolphin attacks by signs put up by the local authority on Crystal Beach

Mr Goto, 23, said he realised the animal was not a shark, but a dolphin when it reared its head from the water.

He said: It kept attacking me and I genuinely believed that I was going to die. I was most worried that I was going to be dragged under the water and further out to sea.

The dolphin continued to attack and bite the swimmer, leaving him with wounds in both his arms, as well as a gash on his left index finger, which needed five stitches.

He was luckily rescued from the aggressive animal, which experts now believe to be a bottlenose dolphin, by a nearby surfer. 

But its possible that rather than trying to hurt Mr Goto, the dolphins bites were its attempt at communication, with scientists suggesting it could have been seeking alternative companionship after being ejected from its own community.

Just as in humans and other social animals, hormonal fluctuations, sexual frustration or the desire to dominate might drive the dolphin to injuring the people it interacts with. Since they are such powerful animals, this can lead to serious injury in humans, said biologist Dr Simon Allen. 

Dolphins rarely prey humans, with experts believing the mammals bites were an attempt at communication (file photo)

Mari Kobayashi, head of the marine biology laboratory at Tokyo University of Agriculture, said that the animal was believed to have committed several attacks over the summer.

He said that the mammal may have been showing signs of loneliness, given that the species is usually found in groups.

For Mr Goto, the frightening experience has put him off returning to the water. He said: Whenever I look at the sea, I can’t help but think a dolphin might be out there. 

Medical teams from the Tsuruga Coast Guard office had been repeatedly summoned to treat people attacked by dolphins.

It advised swimmers who see a dolphin to get out of the water quickly, keep their distance and not attempt to feed it.