Wooden fishing boats believed to originate from North Korea have continuously been drifting near or washing up along Japan's coast, heightening anxiety. The Japan Coast Guard (JCG) estimates they drift from the rich Yamato shallows fishing area in the Sea of Japan, and according to fishing industry sources, the boats have been a source of tension at sea as well.
Around November, an ominous radio warning reached Japanese fishing boats in the Sea of Japan: "There are a lot of boats drifting." Japanese fishing vessels had taken refuge in their harbors due to the rough seas that followed the approach and landfall of typhoons Lan and Saola. When the fishing boats returned to the Yamato shallows after the storms, they found several dozen wooden ships adrift at sea, said Japan Squid Fisheries Association (JASFA) director and Mutsu, Aomori Prefecture fisherman Takamitsu Yoshii, 72.
Around October, Japanese flying squid travel south to the Yamato shallows to lay their eggs, making for good fishing conditions. Japanese ships use fishing lights called "isaribi" to lure the squid at night, catching each animal that nears the boat individually. However, Yoshii says the North Korean boats deploy driftnets and come in close to the Japanese vessels to catch the squid drawn by the light.
In September 2016, a JASFA boat picked up countless small dots on its radar. Usually, Japanese boats are sure to maintain a certain distance from one another while fishing. The association believes that those dots were North Korean fishing vessels. A different JASFA ship also captured video of fishermen in a wooden boat flying the North Korean flag getting squid from a net in July of this year.
Driftnet fishing catches a lot of squid at once, endangering adult squid populations. According to the JASFA, the squid yield for fiscal 2014 was roughly 24,900 metric tons. However, that number dropped to 18,700 tons in fiscal 2016. The poor yield has continued this year, with only some 15,100 tons of squid caught as of the end of November.
The 13 ships of the Ishikawa Prefecture Fisheries Co-operative Associations' Ogi branch in the town of Noto had been preparing to fish in the Yamato shallows in June this year. However, there were so many wooden North Korean boats that they had no choice but to move to the Musashi shallows area near Rebun Island in Hokkaido.
The general manager of the branch said, "(The North Korean ships) are made of wood and so they can easily be washed away in the waves. Operating our ships too close to them risks their nets getting tangled up in our propellers, and an accident could occur." Traveling to the more distant Musashi shallows also uses up more fuel, adding to costs. "Losing a fishing ground is a serious blow. We're preparing ourselves for the decreased yield," he lamented.
After the hold on Japanese flying squid fishing was lifted in June, several ships also departed from Hakodate, Hokkaido, headed for the Yamato shallows, but they too had to abandon fishing there and move to the Musashi shallows. A source from the Hakodate Oshima squish fisheries cooperative told the Mainichi Shimbun, "The fishermen said, 'As soon as we turn on our fishing lamps, the (North Korean) boats would gather around us and it became too dangerous to catch squid.'"