SYDNEY — A clash Wednesday off Antarctica between a Japanese whaler and a boat from a protest group partly bankrolled by former game show host Bob Barker left the anti-whaling vessel badly damaged and each side accusing the other of life-threatening behavior.

The bow of the Ady Gil — a sleek, wave-piercing power boat that resembles a stealth bomber — was sheared off by the Shonan Maru. It was the latest in a series of escalating confrontations between the U.S.-based Sea Shepherd Conservation Society and the Japanese whaling fleet.

Only minor injuries were reported aboard the Ady Gil.

New Zealand's marine safety authority said it was launching an investigation into the clash and that Australia's equivalent body would be cooperating closely.

Japan kills about 1,200 whales a year during the December-February season. Sea Shepherd sends ships to try to stop the Japanese hunt, which Tokyo says is for scientific research but conservationists suspect is a cover for commercial whaling.

Sea Shepherd's aggressive and confrontational tactics have drawn criticism in the past from Greenpeace, which is seeking to change Japanese attitudes toward whaling by cultivating political allies in parliament.

Sea Shepherd's efforts have spawned the Animal Planet TV series "Whale Wars," which has helped win the group high-profile patrons.

Among the group's financial backers is Barker, the former "Price is Right" host who recently gave Sea Shepherd $5 million. The activists named a vessel the Bob Barker, which was near the scene of the clash and rescued the crew of the stricken Ady Gil.

Paul Watson, Sea Shepherd's founder, vowed to continue to confront the whaling fleet.

"The Japanese whalers have now escalated this conflict very violently," Watson said in a statement from aboard another Sea Shepherd vessel, the Steve Irwin, which he is captaining. The vessel, named for the late Australian conservationist, was about 570 miles away from the Ady Gil.

"We now have a real whale war on our hands now and we have no intention of retreating," he added.