The western North Pacific during the 2019 warm season

Coastal trolling and pole-and-line fishery activities in the area from Japan's Kochi Prefecture to Chiba Prefecture in spring and early summer target skipjack tuna (Katsuwonus pelamis), which migrate from subtropical and/or tropical areas. However, a lack of quantitative analysis means that the related effects of the Kuroshio large meander, which emerged for the sixth time since 1965 in August 2017, remain unclear. The data here show very preliminary results from consideration of these effects for several ports in Wakayama Prefecture based on coastal trolling fishery activities. The overall average catch during Kuroshio large meander periods is lower than usual, possibly because the meander shifts fishing grounds with temperatures of 18°C (the lower thermal limit for skipjack tuna) and above farther from port areas. Further analysis is necessary to clarify local skipjack fishing ground presence in relation to the Kuroshio meander.