TOKYO (AP) – A fleet of Japanese whaling ships left for the seas of Antarctica amid protests Tuesday, aiming to kill 850 minke whales – almost double last year’s catch – and expand the hunt to fin whales for the first time.

The expedition is the first under a six-year research whaling program launched earlier this year by the Tokyo-based Institute of Cetacean Research, fisheries ministry official Kenji Masuda said. Japan wrapped up an 18-year study of feeding and migratory habits in March, when the fleet returned from an Antarctic hunt with a haul of 440 minke.

Their meat was sold to restaurants and food wholesalers.

Greenpeace International called on Japan to cancel the latest hunt, calling it commercial whaling in disguise.

The hunt, which is permitted as research under the rules of the International Whaling Commission, is expected to kill 850 minke whales and 10 fin whales, a rarer species.

“In the last survey, we found the number of fin whales has been increasing, so we included them this time,” Masuda said, adding that the fleet plans to expand the hunt again in 2007 to humpback whales. The current research program runs through 2011.

Japan’s research whaling program has for years been a divisive issue within the International Whaling Commission, which banned commercial whaling in 1986 but approved limited hunts for research purposes a year later.

Japan maintains that whaling is a national tradition and a vital part of its food culture. It says whale stocks have sufficiently recovered since 1986 to allow the resumption of limited hunts of certain species. Research hunts, which end up killing the whales, are needed to establish reliable information on whale populations and habits, the government maintains.

Opponents say non-lethal means could be used and that the hunts differ little from commercial whaling because Japan sells the whale meat to restaurants. Last spring’s catch yielded 4.16 million pounds of meat and fetched $26.5 million, Masuda said.

The proceeds fund further research, the government says.

New Zealand Conservation Minister Chris Carter issued a statement Tuesday expressing alarm about Japan’s expanded whale hunt, saying his country was working with other nations to address provisions in the international convention on whaling regulations that make scientific whaling legal but “are out of step with modern conservation approaches.”

“Hunting whales is like hunting tigers (or) gorillas. New Zealanders regard it as unjustifiable,” Carter said.

The current fleet of six ships left the western port of Shimonoseki led by the 8,030 ton Nisshin Maru, and is to return in mid-April.

Tokyo has repeatedly failed to muster the three-fourths majority of International Whaling Commission member nations needed to overturn the commercial whaling ban. Each year, Japan also kills another 210 whales – 100 minke whales, 50 Bryde’s whales, 50 sei whales and 10 sperm whales – during a similar research expedition in the northwestern Pacific.

Norway is the only country that hunts whales for profit. Iceland, like Japan, kills them for research in hunts sanctioned by the International Whaling Commission. The United States and other nations opposed to whaling have said there is no scientific basis for the research.