A leisure fishing boat has collided with what is believed to be a whale off Miura City, near Tokyo, injuring six people.
Coast Guard and local fire department officials say that at around 6:30 a.m. on Tuesday, the boat's captain notified them that it collided with an obstacle believed to be a whale 13 kilometers offshore.
Six men in their 40s to 70s suffered minor injuries to their faces or backs.
The boat later returned to a port without flooding or major damage.
The vessel had reportedly left Maguchi Port in Miura City for squid fishing at around 6 a.m., carrying 15 anglers and the captain.
Coast Guard officials say no one saw a whale, but quoted some passengers as saying they felt an impact of something thrusting the boat up from below.
An expert says there have been many whale sightings in the area.
An advisor for the Institute of Cetacean Research, Kato Hidehiro, said whales have a good sense of hearing in general, so they tend to avoid vessels making engine noise. But he said it is not easy for whales to detect yachts or high-speed vessels such as hydrofoil boats, as their engines make little noise.
Kato said leaving an anchored boat's engine idling so that it keeps making noise reduces or eliminates the risk of whale accidents.