SAKATA, YAMAGATA PREF.- Ken Honma is angry over suspicious boats thought to be of North Korean origin that have driven him and fellow Japanese fishermen out of fertile fishing grounds within Japan's exclusive economic zone in the Sea of Japan.

"Japanese fishing grounds have been taken over," said Honma, 61-year-old captain of the squid fishing boat Wakashio Maru No. 85 in Sakata, Yamagata Prefecture, northeastern Japan.

On July 7, a crew member of a ship believed to be from the unpredictable hermit state pointed what looked like a rifle at a Japanese Fisheries Agency patrol boat within Japan's EEZ, according to government sources.

Increasingly disgruntled, people in the Japanese fishing industry are calling on the government to take measures.

A member of a 13-ship fleet, Honma's boat has caught squid in Yamatotai, a lucrative fishing area in the Sea of Japan, which separates Japan and the Korean Peninsula, for more than 30 years. In late June, about 10 ships believed to be of North Korean origin were spotted in the area.

The small blackish ships each weighing an estimated several tons lacked authorization number plates, unlike South Korean boats that have obtained fishing permits from Japan. They were sailing unlit at night, ignoring whistle warnings.

The unidentified group was catching large amounts of squid by drift-net fishing, a method banned to preserve marine resources.

Japanese ships continued fishing after steering clear of the suspicious boats to prevent the drift nets from getting caught in their propellers.

The number of suspicious ships increased daily and exceeded 100 in early July, prompting the fishermen from Yamagata to abandon the Yamatotai fishing area and head to waters off Hokkaido, northernmost Japan. Boats from Ishikawa and Aomori prefectures were likewise driven out of Yamatotai.

Many squid caught off Hokkaido in this period are small-sized, and the catches of the Wakashio Maru plunged to some one-third of levels in usual years.

Suspected North Korean fishing boats began to be sighted a few years ago, but drift-net fishing was not used until this year, according to Japanese fishermen. (Jiji Press)