Japanese whalers are likely to clash with environmentalists in Antarctica over the next two months as separate fleets head south prepared to confront each other in some of the world's most hostile seas.
On Sunday, the Japanese government's Institute for Cetacean Research (ICR), which is paying for this year's hunt for 950 whales, said five ships were now en route for Antarctica.
Greenpeace International and the Sea Shepherd Conservation Society said they were both sending two ships, equipped with helicopters and inflatables and crewed by more than 100 volunteers.
The pro- and anti-whalers on Sunday night traded insults and appealed for the support of countries they hoped would back their views on whaling.
"Greenpeace and Sea Shepherd are eco-terrorists. They are acting illegally and dangerously. We are very concerned that they will use more and more desperate tactics," said Glenn Inwood, spokesman for the ICR from New Zealand. "Sea Shepherd has said that they are prepared to ram us and we fear that they will endanger the lives of our crews and scientists. We will take whatever action we can."
Paul Watson, of the Sea Shepherd Conservation Society, whose California-based organization has sunk or rammed at least 10 whaling, sealing and other ships in the past 25 years, said his boats would confront the Japanese whalers.
"I think things will be much hotter down south this year. Our objective is to place ourselves in harm's way to protect the whales. We recognize [the Japanese fleet] as a criminal operation and criminal operations are dealt with by aggressive intervention. This is a clear case of justifiable intervention against a criminal operation," Watson said in Melbourne.
Greenpeace International on Sunday said it would be sending its fastest boats to try to stop the whalers.
"Physical confrontation goes against our core principle of non-violence," said Sara Holden of Greenpeace in Amsterdam.
Last year, in extraordinary scenes in the Southern Ocean, the Japanese accused both environment groups of illegal tactics after several incidents when the whalers' "mother ship," the Nisshin Maru, was in collision with the conservationists' boats. The Japanese outran their opponents and killed more than 900 whales for "research" purposes.
Sea Shepherd has since bought a much faster former US coast guard ship, codenamed the Leviathan.
"This time, with the new ship, they can't lose us. If they can't shake us off I am pretty confident we can stop them. If they get violent towards us I suppose it could get very physical. We are quite willing to instigate an international incident over this," Watson said last week as he prepared to leave for the Ross Ice Shelf.
Speaking from Melbourne on Sunday, he said: "Our Leviathan is at sea and on the way south to the coast of Antarctica. It looks as if we will be in a position to confront the Japanese whaling fleet in the Antarctic Whale Sanctuary during the last week of December."
But Greenpeace and Sea Shepherd are not expected to try to help each other.
Although Watson co-founded Greenpeace, the organizations have for many years barely been on speaking terms, developing different philosophies about direct action and protest. Watson has accused Greenpeace of being "the Avon ladies of the environment movement."
Greenpeace, keen not to upset its large membership, tries to distance itself from its more confrontational cofounder.