The Japan Meteorological Agency has revealed that the surface ocean temperatures near Japan soared to record highs for the third successive year, causing significant damage to marine ecosystems. This rise in water temperatures has been attributed to the bleaching of table coral off the Izu Peninsula of Shizuoka Prefecture, emphasizing the detrimental effects of climate change on marine life in the region.
The agency reported that in 2023, the average ocean surface temperature in waters near Japan was notably higher during various periods compared to normal conditions. Specifically, the ocean surface temperature between June and August was 1 degree higher than the 30-year average from 1991 to 2020, indicating a concerning trend of increasing temperatures affecting marine habitats. Moreover, the September-November period and the December-February period experienced even higher temperature anomalies, further highlighting the severity of the situation.
One significant impact of the rising sea temperatures is the noticeable shift in currents, particularly concerning the Black Current along the eastern coastline of the main island of Honshu. The Black Current, which typically flows from south to north before changing direction eastward, has unexpectedly remained along the northeastern Tohoku region since spring 2023. This alteration in current patterns has led to the migration of various fish species to new territories, with reports of unusual catches like giant trevally and spangled emperor appearing in regions previously devoid of such species. The Fisheries Agency has raised concerns over the toll these changes are taking on fisheries and aquaculture industries, with noticeable shifts in fish populations and challenges in seaweed growth due to the warmer waters.