In recent years, anomalous oceanic phenomena have occurred with increasing frequency, and these are also clearly evident around Japan. Among them, the anomalous northward displacement of the Kuroshio Extension has significant scientific and societal impacts on coastal regions. From a physical oceanographic perspective, this anomalous northward displacement of the KE represents a highly unusual situation: in the northeastern coastal areas of Japan, the western boundary current has shifted from the Oyashio (subarctic circulation) to the Kuroshio (subtropical circulation). With this background, we have been monitoring physical environmental parameters (e.g., water temperature, air temperature, and wind velocity) at a coastal station, Otsuchi, in northeastern Japan for 48 years (from 1977 to present), during which water temperatures in 2023, 2024, and 2025 reached record-high levels. Air temperatures in 2023-2025 also show the same high trend as water temperature. These recent records were certainly caused by the anomalous northward displacement of the KE and linked to the recent intense marine heatwave over the western North Pacific. At present, we have begun increasing monitoring stations along the coast in collaboration with stakeholders, such as fishery companies and fishing cooperatives. The stakeholders also regard the anomalous northward displacement of the KE as a matter of serious concern.

Physical oceanographic monitoring,,48 years,,Otsuchi,,Stakeholders