Numerical study of warm water spreading from the Kuroshio front to a coastal water and fishing-ground formation of "shirasu" using a submesoscale ocean model

点击翻译按钮获取中文摘要

Larva and juvenile of pelagic fishes (shirasu) are important targets of Japanese fisheries in coastal waters. The fishing-ground formation has been believed to be related to submesoscale variations such as the Kuroshio frontal disturbances, but details have been little elucidated. To understand the process/mechanism of the shirasu fishing-ground formation, we developed a realistic 1/50-degree submesoscale model connected to a 1/10-degree mesoscale model by using one-way nesting and SSDA method. This study clarified that typical large-scale warm water spreading from the offshore Kuroshio front can supply a large amount of the shirasu to coastal fishing grounds, but they are easily transported away from the coastal fishing grounds, which is associated with short-term fishing-ground formation. In contrast, more preferable long-term fishing-ground formation is expected when relatively weak warm water spreading occurs and the subsequent residence time of coastal water becomes longer.