Japanese whalers fired a harpoon over a Greenpeace boat, throwing one of the environmental group's activists into Antarctic waters, the group said yesterday.
It was the latest of increasingly acrimonious clashes between whalers and environmentalists intent on halting Japan's annual hunt of the marine mammals.
Last week, a whaling factory ship and a Greenpeace vessel collided at sea. Each side blamed the other.
Greenpeace Australia chief executive Steve Shallhorn said a Japanese harpoon came within a meter of a small, inflatable Greenpeace craft.
As it hit a whale and the animal submerged, the harpoon's rope snagged the Greenpeace boat, tossing Canadian activist Texas Joe Constantine into the water.
"We were out defending the whales. We had been out there for about an hour. I was driving our boat and we were in a good position and the whaler fired its harpoon," Constantine explained in a written statement.
"All of a sudden the harpoon line came down on us trapping us between the whale and the catcher," he said.
"The line came tight at that point and threw me from the boat into the water. It was a few minutes before our boat was able to come over and pick me up out of the water," he said.
The Institute of Cetacean Research in Tokyo accused Greenpeace of taking increasing risks in harassing the whaling fleet.
"The fact that the rope fell onto their inflatable and one of the activists fell into the water is entirely their fault," the institute's director General Hiroshi Hatanaka said in a statement.
"Greenpeace are taking more and more dangerous risks to maintain media interest in their [public relations] campaign," he said.
Two Greenpeace ships have been chasing Japan's whaling fleet in Antarctic waters for weeks, hampering the hunt for 850 minke whales and 10 fin whales that Japan says is for scientific research.
The International Whaling Commission's rules permit the research hunt, but Australia and other anti-whaling countries insist the activity is really commercial whaling in disguise.
The meat that is collected from the "research trips" is later sold in Japan.