Anti-whaling activists' high-seas confrontations with Japanese ships forced Tokyo to cut short its annual Antarctic hunt Friday for the first time, a move touted as a victory by the protesters.

Sea Shepherd Conservation Society — which has thrown paint and rancid butter at the whalers and tangled ropes in their propellers — said it would continue its campaign next year.

Japan decries U.S.-based Sea Shepherd as a terrorist group that risks lives in its pursuit of the whaling fleet, which is broadcast in the American television series "Whale Wars."

"We had no choice but to end (the season) to ensure the safety of lives, assets and our ships," Japanese Fisheries Minister Michihiko Kano told a news conference.

Sea Shepherd founder Paul Watson said the milestone of cutting the Japanese hunt short was made possible by beefing up the protesters' equipment and strategy.

"Every year we've gotten stronger," he told The Associated Press by satellite phone from the group's protest ship Steve Irwin, one of three vessels devoted to the campaign.

"We had better equipment, we had a longer-range helicopter ... really, it came down to having more resources," Watson said.

Japanese Foreign Minister Seiji Maehara said Japan has lodged protests with Australia, New Zealand and the Netherlands. Sea Shepherd ships have made port calls in Australia and New Zealand, while its boats sail under the Dutch flag.

"Their obstructive actions are unforgivable," Maehara said. "They threaten the life of vessel crews who are engaged in lawful research whaling activities."

The whale hunts, which Japan says are for scientific purposes, are allowed by the International Whaling Commission as an exception to the 1986 ban on whaling. But opponents say they are a cover for commercial whaling because whale meat not used for study is sold for consumption in Japan.

The Japanese fleet's seasonal quota is 945 whales, but had targeted a catch of 850 whales this season. It will return home with roughly one-fifth of that, the fisheries ministry said.

The ministry said the fleet, which left Japan on Dec. 2 and was scheduled to stay until at least early March, will be returning home soon, though it did not provide an exact timeline.

Sea Shepherd said on Wednesday that it had followed the Japanese fleet's mother ship, the Nisshin Maru, for 2,000 miles (3,200 kilometers). Its three ships will remain in the southern waters to "escort the Japanese ships northward," the organization said in a statement.

In past weeks, protesters have thrown red paint, smoke bombs and rancid butter in bottles toward the whaling ships. They also got a rope entangled in the propeller on a harpoon vessel, causing it to slow down.

Sea Shepherd has waged its campaign of physical intervention against the whalers for seven years, and disputes Japanese government assertions that its activists have engaged in terrorist tactics.

"We haven't committed any crimes," Watson said. "We haven't hurt anybody."

The group's efforts have drawn high-profile donor support in the United States and elsewhere and spawned the popular Animal Planet series "Whale Wars."

Last year, one of the Sea Shepherd's boats sank after colliding with a Japanese vessel. The boat's captain, New Zealander Peter Bethune, was later arrested when he boarded a whaling ship from a Jet Ski, and brought back to Japan for trial. He was convicted of assault, vandalism and three other charges and given a suspended prison term. Bethune has since returned to New Zealand.

Australia maintains the annual hunts breach Japan's international obligations and plans to bring the matter before the International Court of Justice in the Hague.

"I'm glad this season is over and Australia doesn't believe there should ever be another whaling season again," Australian Environment Minister Tony Burke said in a statement Friday.

Japan had temporarily halted the hunt on Feb. 10 and said the suspension would last until conditions were deemed safe. But the government decided to call off the hunt after it deemed conditions had grown too risky.

Greenpeace Japan points to another reason: It says the country simply does not need any more whale meat. The group said it's not surprised by the government's decision because it received a tip late last year that the whaling season would be cut short.

The amount of whale meat in storage has climbed sharply over the last several years. As of December, Japan held 5,093 tons of whale meat in its freezers, according to fisheries agency data.

"Actually, this is the voice of the Japanese public, because the Japanese public has decided it does not want to eat whale meat," said Junichi Sato, Greenpeace Japan's executive director. "And that's the reason why the Japanese government had to decide to come back."

The industry's practices came under domestic scrutiny last year after the fisheries agency reprimanded five officials for accepting whale meat from a company that operated government-funded whaling from 1999 to 2008.

The agency's investigation followed media allegations that whalers and officials were siphoning off meat from the whaling program. Two Greenpeace activists in 2008 stole a package containing whale meat, claiming it was proof of wrongdoing.

A Japanese court in September convicted them of trespassing and theft, ordering suspended prison terms while acknowledging murky gift-giving practices among whaling officials.

Kano, the fisheries minister, did not indicate whether Japan would resume whaling next season, saying instead that it would "examine" the matter.


Associated Press Writers Kristen Gelineau in Sydney and Rod McGuirk in Canberra, Australia contributed to this report.