Tokyo ? Humpback whales are safe – at least for now.

Giving in to U.S. pressure and worldwide criticism, Japan’s government on Friday announced a whaling fleet now in the Southern Ocean for its annual hunt will not kill the threatened species as originally planned. The fleet will, however, kill some 935 minke whales, a smaller, more plentiful species, and 50 fin whales.

Japan dispatched its whaling fleet last month to the southern Pacific off Antarctica in the first major hunt of humpback whales since the 1960s. Commercial hunts of humpbacks have been banned worldwide since 1966, and commercial whaling overall since 1986.

The fleet was to kill 50 humpbacks for scientific research. But the plan generated immediate criticism from environmental groups, which oppose the hunts to begin with but were outraged by the inclusion of humpbacks because they are so rare.

“Whaling issues tend to become emotional, but we hope that the discussion will be carried out calmly on the basis of scientific evidence,” chief government spokesman Nobutaka Machimura said in announcing the halt.

It was a stunning turnaround for Japan.

The U.S., which currently chairs the International Whaling Commission, recently held several rounds of talks with Japan to seek a one to two year suspension of the humpback hunt.

“We applaud Japan’s decision as an act of goodwill toward the International Whaling Commission,” said U.S. Commerce Secretary Carlos Gutierrez.

But he added that Washington and Tokyo still have “opposite views on research whaling.”

Tokyo has staunchly defended its annual kill of more than 1,000 whales as crucial for research purposes. Japan’s whaling fleet is run by a government-backed research institute and operates under an IWC clause that allow the killing of whales for scientific purposes.

Japan said it would halt the humpback hunt pending further IWC discussion.

“But there will be no changes to our stance on our research whaling itself,” Machimura said. “We have made the decision for the benefit of the IWC as a whole.”

The IWC – which oversees whaling activities worldwide – is to hold its next annual meeting in June.

Commercial hunts of humpbacks – which were nearly harpooned to extinction in the 20th century – were banned in the Southern Pacific in 1963, and that ban was extended worldwide in 1966.

The American Cetacean Society estimates the humpback population has recovered to about 30,000-40,000 – about a third of the number before modern whaling. The species is listed as “vulnerable” by the World Conservation Union.

Australia, meanwhile, announced this week it was launching a new push to stop Japan’s annual whale hunt, including sending surveillance planes and a ship to gather evidence for a possible international legal challenge.

“The Australian government welcomes the announcement by Japan that it will suspend its plan to kill humpback whales this season,” Foreign Minister Stephen Smith said in a statement. “While this is a welcome move, the Australian government strongly believes that there is no credible justification for the hunting of any whales.”

Environmental groups also reacted with a guarded welcome.

“This is good news indeed, but it must be the first step towards ending all whaling in the Southern Ocean, not just one species for one season,” Karli Thomas, who is leading a Greenpeace expedition to follow the whalers, said in a statement from on board the ship Esperanza.