Fishermen along the Sea of Japan coast, especially those near Shimane and Fukui prefectures, have been plagued by giant jellyfish since August.
An abnormally large number of Nomura’s Jellyfish have been clogging fixed nets and keeping fish from approaching.
The largest in the jellyfish family in coastal Japanese waters, a Nomura’s Jellyfish, known in scientific terms as stomolophus nomurai, can grow to 2 meters in diameter and weigh 200 kg. Scientists say currents may push the creatures even farther north.
The jellyfish also hurt the fish caught in nets as mucus and poison from their tentacles drastically reduce the catch’s commercial value.
A fixed-net fishing firm in Mihonoseki, Shimane Prefecture, said the problem has cost it some 10 million yen.
“Every day, all our efforts are spent removing the jellyfish from fishing nets,” an official said. A fishing official from Kashima, Shimane Prefecture, said the catch has fallen to the point where some companies are having a hard time paying boat crews.
Toru Yasuda, 64, former director of Fukui Prefecture’s fish-farming center, attributed the large presence of giant jellyfish to cleaner and warmer seawater this year.
The survival rate of the jellyfish was greater this year, Yasuda said, because this year’s rainy season saw a drop in rainfall, resulting in less soil runoff. The higher-than-normal sea temperature has meanwhile led to faster growth of the jellyfish.