Environment Winter Red Tide and Environmental Changes in the Seto Inland Sea - Records of the 2000s

Environment Winter Red Tide and Environmental Changes in the Seto Inland Sea - Records of the 2000s

In the Seto Inland Sea, winter red tides, which were previously rarely observed, began to be observed in the 2000s, raising concerns about their serious impact on the marine environment and the fishing industry. The background of this phenomenon is the rise in sea water temperature during the winter season, which has abnormally increased the proliferation of plankton, which had previously been seasonally suppressed, causing frequent damage to fisheries and disturbance to the ecosystem. The main cause of the red tide is the abnormal proliferation of phytoplankton, and it is believed that the supply of nutrients such as nitrogen and phosphorus, as well as the rise in water temperature due to climate change, contributed to their proliferation.

At that time, concern over global warming was growing internationally, and the Kyoto Protocol came into effect in 2005. Research on global warming countermeasures and ocean conservation accelerated in Japan as well, and the Seto Inland Sea was considered one of the symbolic targets of such research. The Fisheries Research Center and university research institutes conducted detailed oceanographic observations and promoted long-term monitoring of plankton dynamics and water quality fluctuations. In addition, the collection of field data in cooperation with fishermen was also an important element of the project, and there was a growing awareness of the issues throughout the local community.

Related technologies included remote sensing to determine sea surface temperature and chlorophyll concentration, continuous water quality monitoring using ocean buoys, and the development of a red tide prediction model using numerical simulation. This was done in an attempt to predict abnormal plankton proliferation in advance, thereby helping to mitigate damage to fisheries and manage the environment.

The Seto Inland Sea winter red tide was a symbolic example of how climate change directly affects the local marine environment, and at the same time highlighted the importance of science and technology as well as local collaboration. This experience has had a major impact on subsequent marine environmental conservation policies and research on red tide countermeasures.