Fishing boats departing from the port at Habomai in Nemuro, Hokkaido, signaled the start of the fishing season, which saw a shift one week earlier than usual due to the warming seas in the area. Data from the Japan Meteorological Agency revealed that the average sea surface temperature in the first half of 2022 was the highest recorded, surpassing the previous record from 1998.
Experts pointed to the abnormal flow of the Kuroshio Current as a significant factor in the increased sea temperatures, with the current deviating from its usual path and moving northward along Japan's main island, Honshu. This shift is believed to be linked to changes in westerly wind patterns, possibly accelerated by global warming, leading to anomalies like ocean heat waves which are now occurring more frequently in Japanese waters.
The impact of rising sea temperatures and ocean heat waves on marine life and fishing activities is evident in Hokkaido, with reports of challenges in catching salmon and trout towards the end of fishing seasons in recent years. Similarly, the northward movement of the Kuroshio Current has contributed to phenomena like red tides off the coast, affecting the undersea environment and causing an increase in toxic phytoplankton. As these trends continue, experts warn of the increasing likelihood of ocean heat waves and their profound effects on marine ecosystems and fishing industries around Japan.