The Japanese whaling fleet was preparing for a three-month hunting operation in the Antarctic on Monday.

In the face of fierce criticism, Tokyo defended the downsized hunt, saying it was necessary for research that would help conservation and stock management.

The fleet is scheduled to set sail on Tuesday, despite a warning from the International Whaling Commission (IWC), which says Japan has not proven its case that killing the whales will provide any significant scientific value.

The Japanese Fisheries Agency, however, said it was the only way to obtain information on the maturing age of whales. In a joint statement with the Foreign Ministry, the agency detailed the plan it had submitted to the IWC: to capture up to 333 minke whales, which is roughly one-third of what they had formerly killed in a given year, every twelve months for up twelve years.

The plan will be reevaluated for efficacy after six years.

Australian disapproval

The IWC issued a universal ban on commercial whaling in 1986, but despite strong international criticism, Japan has continued to hunt for whales using a loophole that allows the conducting of scientific research.

Australia brought an International Court of Justice case against Japan over the country's whaling in 2014, when The Hague ruled that the operations were not scientific and forced Tokyo to revise its plan.

Attorney-General George Brandis said that his government was "very disappointed" by Japan's decision to continue whaling. He said that should diplomacy fail, Canberra would consider sending out Customers and Border Protection Service ships if the four Japanese boats traversed Australian territory.

es/tj (AP, dpa)