TSUYOSHI NAGANO Asahi Shimbun 18 Jun 14;
Rising sea temperatures are pushing Japanese common squid populations toward the Korean Peninsula, leaving Japanese fishermen with dwindling catches and fears for the future of their livelihoods, industry officials said.
Japanese common squid, which account for 80 percent of the domestic squid catch, used to be caught all along the Sea of Japan coast of Honshu for more than half a year. But the squid are now veering away from Japan on their southern migration run, resulting in a shortened fishing season.
According to the Japan Squid Fisheries Association, squid fishermen now must travel long distances to reach remote fishing grounds while competing against an increasing number of Chinese fishing vessels.
The situation has been particularly hard on small boat fishermen.
In Sado Island, Niigata Prefecture, the number of squid fishing boats has decreased from 101 in 1998 to 16.
“Due to the cheap prices of squid, rising fuel prices and global warming, everyone has given up fishing,” said Tadao Katagiri, the 66-year-old head of a local squid fisheries association.
Thanks to the change in fishing grounds, South Korea’s average annual catch of common squid between 2002 and 2012 increased 3.4 times to 110,000 tons. During the same period, Japan’s annual catch dropped by 35 percent to 80,000 tons.
In the 1980s, the monthly catch of common squid off the coast from Akita to Yamaguchi prefectures exceeded 2,000 tons from May to December, according to a study by Hideaki Kidokoro, who heads the resources management group of the Japan Sea National Fisheries Research Institute in Niigata.
However, in the 2000s, that catch level was only seen from May to July, he said.
Kidokoro attributes the decrease to warmer water temperatures from spring to autumn. In the Tsushima warm current region that runs along the Sea of Japan coast, the water temperature in autumn rose from around 19 degrees to 20 degrees in 1998, he said.
Squid spawn eggs from autumn to the year-end in the Sea of Japan from the Sanin Region to western Kyushu. The young common squid normally move up to northern areas of Japan by the summer before returning south to their spawning grounds.
But now, instead of migrating south along the Japanese coast, the squid are moving toward the cooler waters off the Asian continent, including the Korean Peninsula.
The spring to autumn temperatures there are apparently more suitable for the squid than those for the waters off Japan.
