The Japanese government confirmed in early November that its whaling fleet would once again leave port in early December to carry out what Japan claims is "research whaling" in the icy waters of the Antarctic.

However, the exact date the vessels will slip their moorings, and the areas in which they will operate, are being kept a closely guarded secret.

And for good reason. Criticized around the world as thinly disguised commercial whaling - in large part because hundreds of whales are slaughtered and the meat ends up being served in Japanese schools and restaurants - the cull is fiercely opposed by environmental groups.

Of all the anti-whaling activists, none is more outspoken - or confrontational - than the Sea Shepherd Conservation Society, which has harassed the Japanese fleet every year since 2005.

This year, the group has vowed for the first time to take the battle to protect the whales into Japanese territorial waters.

Sea Shepherd's team of vessels, crewed by 110 volunteers from around the world, is heading North through the Pacific, and the organization has set itself the target of not permitting the whalers to catch a single "specimen" this season.

Confrontation off Japan

"The plan is for our fleet to be meeting their fleet in the North Pacific off Japan," said Peter Hammarstedt, deputy leader of Sea Shepherd, in a statement. "We are planning to take the battle pretty much up to Japan itself."

"The goal for us is to have a zero-kill quota of whales," he added. "If we can get to the Japanese fleet early, hopefully they will cut their losses."

Whaling in Japan can trace its roots to small-scale coastal operations as far back as the 12th century, but the industry was ramped up in the 20th century as it sought to feed a burgeoning population with limited domestic food resources.

Japan opposed a moratorium on commercial operations imposed by the International Whaling Commission in 1986 and has since used a loophole in the rules that permits scientific research to harpoon hundreds of whales every year.

Since 1988, Japanese whalers have caught more than 14,200 whales, the majority being minke whales, but also including fin, sperm, sei and Brydes whales.

Japan defends its continued program by insisting that there are sufficient stocks of whales in the world's oceans and that whaling is a Japanese cultural practice that foreign countries should not interfere with. Japanese commentators have also suggested that opposition is rooted in covert racism.

Japan's research on whales is carried out under the auspices of the Institute of Cetacean Research, a privately owned, non-profit organization. The ICR did not respond to telephone and e-mail requests for comments on the whaling fleet's planned operations this season. Sea Shepherd, however, has been a lot more forthcoming about its plans.

"Eco-pirates"

Describing themselves as "eco-pirates," the organization has launched what it says is the biggest and most aggressive mission ever to stop the slaughter of whales.

The three-strong fleet is led by the SSS Steve Irwin, named after the late Australian wildlife expert nicknamed "The Crocodile Hunter." The faster SSS Bob Barker is designed to locate the Japanese ships, while the SSS Brigitte Bardot is a technologically advanced vessel that in 1998 circumnavigated the world in just 74 days and is now used as a scouting ship.

Sea Shepherd is also deploying a new ship, the SSS Sam Simon, although its duties and capabilities are shrouded in secrecy.

This year's campaign - named Operation Zero Tolerance - is likely to bring the whalers and environmentalists into confrontation long before they reach the Antarctic Ocean. The aim is improve on last year's campaign and avoid ships from the Japanese Coast Guard, which are expected to once again accompany the whalers.

In that effort, the Japanese were only able to catch 26 percent of their quota for the year, after environmentalists hurled bottles of reeking butyric acid, which smells like rancid butter fat, onto the decks of the whaling ship and the whalers retaliated with water cannons.

Still, Captain Paul Watson, who founded Sea Shepherd in 1981, said the 267 whales that were culled is "267 too many." And this year, the environmental group believes it holds the whip hand.

In the words of Sea Shepherd deputy leader, Peter Hammarstedt: "We have never been stronger and the Japanese whalers have never been weaker."

"We need to take advantage of our strengths and their weaknesses, and we need to bring this campaign home to Japan," Hammarstedt said.