Reasons for the Decline in Catches as Revealed by Long-Term Data from the Actual Operation of the Sea Urchin Fishery Hemicentrotus pulcherrimus in Mikuni, Fukui Prefecture, Japan

Dive fisheries are widely practiced in coastal areas worldwide owing to their minimal equipment requirements and extensive historical background. Female divers in Korea and Japan have extensive knowledge of the local coastal environment and engage in sustainable fishing practices. However, the number of divers and their catches has been declining. In this study, long-term catch and effort data were collected to investigate the reasons for the decline in the catch of the sea urchin, Hemicentrotus pulcherrimus, in Mikuni, Sakai City, Fukui Prefecture, Japan. A significant correlation was observed between catch and effort, and the main reason for the decline in catch was a reduction in fishing effort. Fishermen have voluntarily limited their fishing efforts to prevent the depletion of natural stocks, and a decrease in the number of fishermen has contributed to this reduction. In addition, regulations on catchable size and fishing season were implemented. However, natural stocks appear to have declined. Although sea urchin fisheries have been sustainably practiced for a long time, current fishery management and regulations appear inadequate. Therefore, sustainable fishing requires identifying the factors that affect stock fluctuations and updating management practices.