Japanese vessels left a port in northern Japan on Tuesday to catch around 30 minke whales in the northwestern Pacific, a whaling group and the Fisheries Agency said.

The vessels plan to conduct what the government refers to as research whaling, between 50 to 90 kilometers off the Sanriku coast.

The whaling will continue until mid-August so that the stomach contents of the catch can be analyzed and the gathered data used to manage marine resources, according to the agency and the Association for Community-Based Whaling.

A pair of vessels left the port of Hachinohe, Aomori Prefecture, in the morning.

"We aim to collect scientific data to be able to begin commercial whaling again," said Yoshifumi Kai, the association's representative, at a ceremony marking the ships' departure.

In May, the agency submitted to the International Whaling Commission Japan's plan to catch a total of 170 minke whales per year in the northwest Pacific, with 47 caught so far in June and July.

The maximum number of whales to be caught in the Pacific coastal region, which includes the area off the Sanriku coast, has been set at 80 annually.

Previously Japan conducted coastal research whaling in the region from the port of Ayukawa in Ishinomaki in neighboring Miyagi Prefecture and the port of Kushiro in Hokkaido. But it has expanded its research area from the current fiscal year to conduct detailed research.

The next phase of whaling in the region will be launched out of Kushiro in the fall.