Japan's whaling fleet set off yesterday towards the Antarctic Ocean for a hunt that will include famed humpback whales for the first time, defying Western protests that the move will inflame tensions.
Japan argues that whale populations have recovered enough to allow a managed catch, but environmentalists have vowed in turn to "hunt the whalers" to save the humpbacks.
The fleet took off for its five-month voyage after a ceremony in the western port town of Shimonoseki that included the head of Japan's Fisheries Agency, an official said.
The fleet is led by the 8,044-tonne Nisshin Maru, which has been repaired since a fire that forced Japan to cut short its last Antarctic hunt.
The environmental movement Greenpeace said that its Esperanza ship is waiting outside Japanese coastal waters and will track the whalers in Antarctic waters, shooting video to show the public.
"The threatened humpbacks targeted by the whalers are part of thriving whale watching industries elsewhere," Greenpeace expedition leader Karli Thomas said in a statement issued aboard the Esperanza.
"The whaling fleet must be recalled now. If it is not, we will take direct, non-violent action to stop the hunt."
Japan kills more than 1,000 whales a year in the Antarctic and also the Pacific Ocean using a loophole in an international moratorium that allows catching whales for research. Only Norway and Iceland defy the moratorium outright.
This year, Japan is expanding the catch to include 50 humpback whales, which are celebrated for their complex songs and acrobatic displays.
The expedition also plans to kill 50 fin whales -- the world's second largest animal after blue whales -- as well as 850 smaller minke whales.
It will be the first time that Japan has hunted humpback whales since an international moratorium on the species took effect in 1966 because of overhunting. The former Soviet Union also defied the moratorium.
Western conservationists say that humpback and fin whale populations are still vulnerable. Australia has warned that killing humpbacks would seriously worsen an already bitter feud with Japan on whaling.
Humpbacks migrate northwards along Australia's coast to breed each year. Their slow and majestic progression each year draws some 1.5 million whale watchers, pumping US$225 million into Australia's economy.
"It's important that Japan understands that the inclusion of humpbacks will have an impact on perceptions of Japan in Australia," Australian Environment Minister Malcolm Turnbull said earlier this year.
Japan counters that Western nations are insensitive to its culture and that whale populations are recovering.
Japan makes no secret that the whale meat goes onto dinner plates and also says that "lethal research" helps keep data on the giant mammals.