A fleet of four whaling ships set sail Saturday to hunt up to 51 minke whales in coastal waters through late May as part of he government's scientific research whaling program.

The Association for Community-Based Whaling, a nonprofit organization set up for coastal research whaling, plans to hunt in an 80-km (50-mile)radius area from Ayukawa port in Ishinomaki, Miyagi Prefecture, to study the animal's impact on marine resources by checking stomach contents and other indicators.

In March 2014, the International Court of Justice ruled that Japan's research whaling in the Antarctic Ocean violated the International Convention for the Regulation of Whaling, ordering Japan to halt its research whaling there.

In response, Japan reviewed parts of its whaling program in the northwestern Pacific and has since scaled down operations.

Japan's research whaling has come under fire as the meat from the hunted animals is sold in markets after the animals are examined. Critics say it is a cover for commercial whaling.

Coastal research whaling is conducted off Ishinomaki in the spring and Kushiro, Hokkaido, in the fall.