Four small ships in Hokkaido left the port city of Kushiro on Sunday to hunt minke whales along the Pacific coast for what was described as research purposes.

The fleet plans to catch up to 51 minke whales off Kushiro through the end of October to survey the impact of the mammal's predation on coastal fishing by checking the contents of their stomachs. Meat from the whale will be sold as food.

It is the first research whaling to be conducted off Kushiro since the International Court of Justice in The Hague in March ordered Japan to halt whaling in the Antarctic Ocean because its much-touted research whaling was deemed unscientific.

From April to June, however, the Japanese fleet engaged in Pacific whaling off the Sanriku region in the northeast.