A Japanese whale hunting vessel set off Tuesday for the Antarctic seas beefed up by Coast Guard patrol boats in anticipation of another fierce interference from Sea Shepherd's anti-whaling ships and activists.

The 720-ton Yushin Maru was seen leaving a port in Shimonoseki in western Japan but fishery officials were mum about details of the mission citing security reasons. But the Japanese government had submitted a plan to catch 900 minke and fin whales to the International Whaling Commission.

In February, the Japanese whaling fleet brought home 172 whales in a hunt cut short by a month due to clashes and collisions with Sea Shepherd ships. New Zealander Peter Bethune also used a jetski to board a whaling ship resulting in his arrest, trial and conviction in Japan for assault, vandalism and other charges.

The two sides are expected to clash again with the Sea Shepherd calling its effort to obstruct the latest whaling expedition "Operation Divine Wind." The word "divine wind" is "kamikaze" in Japanese and refers to the suicide missions carried out by Japanese air force pilots in World War II.

The Japanese government justifies the whale hunt as for scientific research though the catch ends up in Japanese restaurants. Whale hunters also have the support of the Japanese public.

Australia and New Zealand are among the countries opposing whaling citing the declining population of the ocean mammals.