The Sea Shepherd anti-whaling fleet docked in Australia Wednesday claiming victory over Japan, as Canberra indicated fugitive founder Paul Watson would not face arrest if he came ashore.
The ships Steve Irwin, Bob Barker and Sam Simon returned from a bitter campaign in the Southern Ocean in Antarctica with an estimated Aus$1.0 million (US$1.03 million) damage bill after run-ins with Japanese whalers.
Their fourth ship, the Brigitte Bardot, was at an undisclosed location with Watson, wanted by Interpol after skipping bail last July in Germany, thought to be on board.
The ships left port in November and Bob Barker captain Peter Hammarstedt said it had been the most successful, but most dangerous, campaign of the nine they have carried out so far.
"It's been a long campaign, it's certainly been the most dangerous to date. Never before have the Japanese whalers been as brazen, as reckless, as violent as they have been this year," he said in Melbourne.
"My vessel carries scars from battle and those scars were delivered by illegal Japanese whaling boats that were killing whales unlawfully in Australian Antarctic territorial waters."
The militant environmental campaigners claim the Japanese fleet "repeatedly rammed" their boats but Japan's Institute for Cetacean Research has accused Sea Shepherd boats of targeting its vessel, the Nisshin Maru.
Japan, which says the hunt does not breach an international moratorium on commercial whaling because it is done in the name of "scientific research", had set a quota of more than 1,000 minke and fin whales this season.
But Sea Shepherd claimed only 75 were caught, the smallest haul yet.
Sea Shepherd director Bob Brown, the founding leader of Australia's Greens Party who assumed command of the campaign from Watson, said it was "a great outcome".
"Many of the whales are heading to Australia right now rather than as lumps of meat on a factory ship heading to Tokyo," he said.
Watson himself spent the campaign on board the Steve Irwin but there was no sign of him in Melbourne.
He is wanted after skipping bail in Germany where he was arrested on Costa Rican charges relating to a high-seas confrontation over shark finning in 2002.
Brown said Canberra must allow him into Australia without the risk of arrest.
"The Australian Federal Court has ruled that Japanese whaling is illegal -- they are breaking Australian law, and Sea Shepherd is upholding Australian law," he said.
"We need the chief upholder of Australian law in Antarctic waters, Paul Watson, to know that he can come freely onto these shores knowing that he will not be harassed by the long arm of Tokyo."
Attorney-General Mark Dreyfus indicated that Watson would not be arrested if he came to Australia.
"The Australian government does not provide assurances whether a person will be subject to extradition proceedings either now or during the future," he said, without saying whether Canberra has received an extradition request.
"But as I have made clear, a person cannot be extradited from Australia in the absence of an Australian warrant and the approval of the Australian government.
"That said, I can confirm that Mr Watson is not subject to any arrest warrant in any Australian government juristication."
Canadian Watson claims the charges he faces are part of a "politically motivated" attempt led by Japan to put an end to his efforts against whaling.