Japan has recalled its whaling fleet from the Antarctic following confrontations with activists from the Sea Shepherd marine conservation group, the government has said, in a move that has raised hopes that the hunts will be halted altogether.
The decision to cut short this year's hunt is a further blow to the industry, which has been the target of international pressure and revelations of corruption at home.
The agriculture minister, Michihiko Kano, said the hunt, which was due to last until the middle of March, had been called off because of safety concerns.
"We had no choice but to end the season to ensure the safety of lives, assets and our ships," he told reporters. Asked if Japan would resume whaling next winter, Kano said: "We'll examine the situation in detail and then come to a decision."
Sea Shepherd's founder, Paul Watson, described the announcement as a victory for anti-whaling activists.
"Every year we've gotten stronger," he told Associated Press from the Steve Irwin, one of three boats the group has in the Antarctic. "We had better equipment, we had a long-range helicopter. Really, it came down to having more resources."
The Japanese government routinely condemns Sea Shepherd as a terrorist organisation, claiming its tactics have put crew members' lives at risk. But Watson said: "We haven't committed any crimes. We haven't hurt anybody."
Australia, a vocal critic of the whale hunts, welcomed the move. "I'm glad this season is over, and Australia doesn't believe there should ever be another whaling season again," the environment minister, Tony Burke, said.
Last year Australia filed a complaint with the international court of justice in The Hague in an attempt to get the hunts banned. A decision is expected in 2013 at the earliest.
The Japanese fleet had targeted a catch of 850 whales this season, but will return with about one-fifth of that, the agriculture ministry said. Sea Shepherd claimed it had kept the fleet's haul to below 100 whales, its lowest ever catch.
Japan kills about 1,000 whales every year, using a clause in the International Whaling Commission's 1986 moratorium on commercial whaling that allows it to engage in "lethal research" into whale populations.
The meat from the hunts is sold on the open market, but weak consumer interest has created a stockpile of more than 6,000 tonnes, according to a recent report by the Japan-based Dolphin and Whale Action Network.
The ministry did not say then the fleet of four vessels and 180 crew would return. It left port in December and was supposed to return in April.
The decision comes two days after Japan said it was suspending its controversial whale hunt after another clash with Sea Shepherd.
Ministry officials claimed that Sea Shepherd's pursuit of the mother ship, the Nisshin Maru, had made it impossible for the hunt to continue. The fleet's other vessels are unable to operate unless the Nisshin Maru is present to haul in harpooned whales and process them.
During its seven-year campaign in the Antarctic, Sea Shepherd has hurled rancid butter aboard whaling ships, attempted to entangle propellers and distracted Japanese crews with flares and infrared beams. In recent days it has blocked the Nisshin Maru's stern, reports said.
In the most high profile incident, a Tokyo court gave a Sea Shepherd activist a two-year suspended prison sentence after he boarded a whaling ship last February.
Peter Bethune, a New Zealander, had climbed aboard the Shonan Maru 2 under cover of darkness to deliver a bill for damage to the Ady Gil, the group's hi-tech powerboat, which sank after a collision with the Japanese ship the previous month.
Sea Shepherd said it would stay with the Japanese boats, which are currently sailing north, until it was sure they had left the Southern Ocean whale sanctuary.