TOKYO — Japanese fishermen herded dolphins into a cove made famous by an Oscar-winning documentary about the hunt but did not kill any Friday, as conservationist groups ramped up scrutiny of the annual slaughter.

An official in the seaside village of Taiji, depicted in the film "The Cove," said a handful of the best-looking dolphins were kept to be sold to aquariums, but the rest were set free Friday morning. He declined to give details.

The decision to set most of the dolphins free marks a departure from past practice.

Conservationist group Sea Shepherd said it has been monitoring Taiji with a small crew of activists this week, and urged people to come to the village to help save the dolphins.

Dolphins swim in pods in the ocean. Taiji fishermen herd them by scaring them with noise into the cove, save some for aquariums and kill the rest, piercing them repeatedly until the waters turn red with blood.

It was not clear where the activists had stationed themselves Friday, but it was unlikely they would be able to see any slaughter since the cove is hidden from the village itself. But they would likely be able to watch the fishermen return to the village with their catch.

The shocking depiction of the slaughter in "The Cove" has launched calls for the hunt to be stopped. The film, which stars Ric O'Barry, won this year's Academy Award for best documentary.

On Thursday, a day after the annual hunt began in Taiji, O'Barry, 70, took a petition calling for its end with 1.7 million signatures from 155 nations to the U.S. Embassy.

O'Barry, the former dolphin trainer for the 1960s "Flipper" TV show and a longtime dolphin activist, has received threats from a violent nationalist group and skipped going to Taiji this year, a trip he normally makes to protest the hunt. He said he had been advised by Japanese authorities not to go.

Taiji residents say the criticism the town has received from the West is unfair because residents are merely trying to make a living in an area where a rocky landscape would make farming and livestock-raising difficult.

Nationalist groups say criticism of dolphin hunting is a denigration of Japanese culture.

The Japanese government allows a hunt of about 20,000 dolphins a year, and argues that killing them -- and whales -- is no different from raising cows or pigs for slaughter. Most Japanese have never eaten dolphin meat and, even in Taiji, it is not consumed regularly.

The government is also critical of Sea Shepherd, which has harassed Japanese whaling ships. In July, a Tokyo court convicted New Zealander Peter Bethune, a former Sea Shepherd activist, of obstructing a Japanese whaling mission in the Antarctic Ocean, assault, trespassing and other charges. He was deported.

"I'm not losing hope. Our voice is being heard in Taiji," said O'Barry, who has campaigned for four decades to save dolphins not only from slaughter but also from captivity.