This year's dolphin-hunting season kicked off Tuesday in the whaling town of Taiji, in Wakayama Prefecture, using a traditional "drive-hunting" method that animal-rights groups at home and abroad say is cruel.

The controversial hunting technique, in which fishermen herd dolphins and small whales into a cove where they can be killed or captured, was depicted in the 2009 documentary film "The Cove," which won an Academy Award.

A fleet of fishing boats spotted a school of cetaceans some 12 kilometers off the coast at around 8:50 a.m., and captured three bottlenose dolphins and a Risso's dolphin after driving them into a cove.

They were each around 3 meters long and will be sold to aquariums, according to participants in the hunt.

Cetaceans caught in the hunt are either sold to aquariums or consumed as food.

"We got off to a wonderful start as we caught dolphins from day one," said Yoshifumi Kai, a senior member of the town's fishing cooperative.

Japan's whaling has drawn fresh attention from anti-whaling countries after Tokyo withdrew from the International Whaling Commission and restarted commercial whaling last year.

As an IWC member, Japan had halted commercial whaling in 1988 but hunted whales for what it claimed were research purposes, a practice criticized internationally as a cover for commercial whaling.

But the traditional hunting technique conducted in waters near the town is not subject to controls by the IWC and has been conducted for years.

During the drive-hunting period through next spring, police and the Japan Coast Guard will boost security to prevent activists from obstructing hunting, maintaining a 24-hour presence at stations temporarily set up in the town.