Squid-fishing associations from Japan and South Korea plan to work together to urge their governments to work harder at countering illegal fishing by Chinese and North Korean ships in the Sea of Japan, according to the Japanese group.

The Japan Squid Fisheries Association said Monday that 200 to 300 unidentified vessels repeatedly fished illegally in a prime spot for Japanese flying squid from late September to the end of October, interfering with Japanese and South Korean vessels allowed to fish there.

Because South Korea fishermen share the same concerns about the area, the Japanese association held a meeting with a South Korean fishing group Thursday, where they agreed to work together to push their governments to take measures to crack down on illegal fishing.

They also agreed that their governments should press the Chinese government to address the situation.

“The unidentified ships may include those that are not under the control of the Chinese government and there is a limit in what private-sector groups can do,” said Kyoichi Kawaguchi, the head of the Japanese association. “We hope measures will be taken under an international framework.”

Fishermen have been struggling with poor catches of Japanese flying squid, fueling concerns that overfishing will further reduce marine resources in the area.

The Japanese association has not been able to confirm the names and other details of the unidentified ships, but characters written on the ships indicated that they were Chinese or North Korean.