Japan’s whaling fleet is preparing to leave for the Antarctic for a three-month hunt despite protests from opponents who say Tokyo has not proved that whales need to be killed for research.

The announcement comes days after Japan submitted its final plan to the International Whaling Commission (IWC) after its scientific committee said earlier this year it was not convinced that whales needed to be killed for research on whale stock management and conservation.

The expedition, which leaves today, will be the first since the International Court of Justice (ICJ) ruled last year that the hunts were not truly scientific, forcing Tokyo to revise its Antarctic whaling plans.

Last year, Japan did go to the Antarctic but its research did not involve killing any whales.

Japan says lethal sampling is indispensable for obtaining data on the maturing ages of whales.

Under Tokyo’s scaled-down proposal, it plans to catch up to 333 minke whales, about one-third of what it used to kill, each year over the next 12 years, the fisheries agency and the foreign ministry said. The plan will be evaluated after six years.

Committee not convinced whales needed to be killed for research on whale stock management and conservation

Japan’s actual catch has fallen in recent years, in part because of declining domestic demand for whale meat.

Protests by the anti-whaling group Sea Shepherd also contributed to the lower catch. The government has spent large amounts of tax money to sustain the whaling operations.

The IWC imposed a commercial ban on whaling in 1986 but Japan has continued to kill whales under an exemption for research.

Australia, which brought the ICJ case against Japan, said it might send a boat to shadow the Japanese fleet.

Attorney-General George Brandis told the Senate that Australia was “very disappointed” by the resumption of whaling and had taken the matter up at “the highest levels” in a bid to get Japan to change its mind.

If diplomacy fails, Australia will consider sending a customs and border protection service patrol boat, Brandis said.

He did not say what role such a boat might play, but it would probably try to gather evidence of illegal conduct.

Whaling in Japan

An anti-whaling protester in Melbourne, Australia, in 2007.

• Hand-harpoon whaling began as early as the 12th century in Japan, the pro-whaling Japan Whaling Association says.

• Antarctic whaling was initially dominated by Britain and Norway, but by 1969, only Japan and the Soviet Union were whaling in Antarctica.

• One year after the IWC’s 1982 commercial whaling moratorium came into force in 1986, Japan began its scientific whaling.

• Japan cites Article VIII of the International Convention for the Regulation of Whaling as giving the right to take whales for scientific research.

• Iceland and Norway are the only countries to ignore the moratorium and conduct commercial hunts.

• Asking Japan to abandon its whaling culture would be like asking Australians to stop eating meat pies, or the English to give up fish and chips, the pro-whaling JWA says.

• JWA argues that the Southern Ocean whale sanctuary, established in 1994, only bans commercial, not research, whaling.

• Critics say scientific whaling is commercial whaling in disguise. Others say whaling is more of an invented than actual traditionand is only really supported by a vocal minority of conservative nationalists.

• The JWA says its goal is to answer key questions about whales to better manage them. It says selling whale meat obtained through scientific research is required by a rule stating that research by-products are not wasted.