[A-CG44] Kuroshio Large Meander

[ACG44-P01] Ocean conditions changes associated with the Kuroshio large meanders and its impact on fishing

★Invited Papers

*Takashi Setou¹, KUSAKA AKIRA¹ (1.Japan Fisheries Research and Education Agency)

Keywords:Kuroship, Fishing

When the Kuroshio large meander occurs, the ocean conditions in the surrounding areas including coastal areas change, and these changes also often impact on fishing. In this presentation, some case studies will be presented based on the past papers and the latest findings from several viewpoints. First, we would like to introduce some examples of the changes in fishing grounds caused by variations of water temperature. When the Kuroshio largely meanders off the Enshu-nada, the waters of the nada and the Kumano-nada become warmer due to the Kuroshio branches or the Kuroshio counter current. As a result, seaweeds exposed to high water temperatures do not grow well, while warm-water migratory fish such as skipjack are often caught well. On the other hand, in the west of Cape Shiono-misaki, where the Kuroshio takes the offshore path and the temperature becomes lower, it has been reported that some of the farmed yellowtail died. Changes of the fishery grounds resulting from current variation are more complicated. In the case of juvenile anchovy which is passively carried to the current, the fish catch status differs between the 2004-2005 large meander event and the 2017 event, and even during the latter there are good and bad fishing seasons. The fact means the current pattern, in coastal areas associated with the Kuroshio large meander, is not unity but multiple or complex. Therefore, the Kuroshio large meander events often affect the formation of fishing grounds in the surrounding area due to some changes in ocean conditions, but it can also affect the fishing itself. For example, during the 2017 Kuroshio large meander event, stormy coastal currents named the Kyucho caused by counter currents frequently occurred in a wide area from the Enshu-nada to Cape Muroto-misaki, resulting in destroying set nets and causing serious damage to fisheries. Further examples will be given in the presentation.