Eighteen people were injured this summer in a coastal city, likely by a lone dolphin that broke away from its pod.
TOKYO — A lone bottlenose dolphin is believed to be behind a string of attacks on beachgoers in an eastern coastal city, likely out of loneliness.
Lonely Dolphin: The Surprising Culprit Behind Recent Swimmer Attacks in Japan
Eastern broadcaster NHK said on Aug. 20 that a man in his 50s was bitten on both hands that morning by a dolphin that approached him as he tried to chase it away at a beach in Tsuruga, a city in Fukui Prefecture. He became the 18th big fish target since July 21 and the second one in the coming two days.
In the last 3 years, 48 people in your space have mourned dolphin tidbits, NHK said, including some with damaged bones.
Although unconfirmed, it is widely believed that the attacks in recent years were carried out by the same male bottlenose dolphin. The attacks have always involved a single dolphin that appears to be alone, which is rare considering bottlenose dolphins are a highly social species that stick together in groups.
Injuries on the dorsal fin of the big fish interested in the Aug. 20 attack match those of a dolphin spotted off the coast last year, said Tadamichi Morisaka, a researcher at the Cetacean Studies Centre at Japan’s Mie University who has visual images. Dorsal fins are unique to each dolphin, as are fingerprints.
“It’s reasonable to expect that they are the exact individual,” Morisaka told NHK.
In an email to NBC News, Morisaka noted that it’s rare for bottlenose big fish of that species to approach humans, let alone bite them. In this case, the dolphin appears to have become accustomed to interacting with humans after doing so for several years.
He said the tidbits seem lively, presenting the big fish as “especially likes to interact with human beings,” instead of attacking or hurting them.
But because dolphins have many sharp teeth, even a mild bite can injure humans.
Swimmers in the area are warned to get out of the water if they see a big fish. When a big fish was spotted around the swimming place on a coast in the municipality of Mihama on Aug. 21, a beach staff member coaxed it out to sea with the help of water skis.
“Last year, there were many incidents where swimmers were bitten by big fish. Some even suffered bone fractures that required more than 10 stitches,” reads a note from the Coast Guard, adding that in many cases swimmers were bitten when they approached dolphins to touch them.
Signs and symptoms posted by the Wakasa-Mihama tourist association warn that while big fish are “generally calm creatures,” if provoked, they can draw blood with their teeth or drag humans into the sea.
The creature concerned in the aggression seems to be a “sociable isolated big fish” that has separated itself from its usual dolphin community, although it is not obvious why, said Elizabeth Hawkins, chief executive and founding director of Dolphin Studies Australia.
By shedding themselves, big fish“try to satisfy their natural social drives with other species, and it is usually humans that they seek out,” she said.
Male bottlenose big fish tend to form close bonds with each other, which they reinforce by chasing, biting and touching each other, even in a sexual way.
So even though they are socially isolated, Hawkins said, “they can be quite aggressive, they can be quite competitive, they can bite.”
“This is all region of their day-to-day techniques within the big fish neighbourhood,” he said. “But closer to humans, it’s something that can be quite dangerous and can cause very serious accidents.”
“So in the context of this animal, it’s true that we need to make sure that it’s given space.”