|Abstract or Summary
- Each year, over 20,000 metric tons of tuna are supplied to the Japanese market, of which 40% are caught by domestic vessels. Although the Japanese tuna market is large, little is known about the supply chain and the Japanese tuna fisheries’ behaviors. In this study, we investigate how Bluefin tuna are caught in Japanese EEZs and brought to consumers. To do this, we use the reported landings data, central wholesale market data, and conduct interviews. To represent the qualitative information gathered via the interviews and to complement the quantitative analysis, we develop a model of migrating fish stocks with multiple fishing entities. We identify that Bluefin tunas are caught mainly by pole-and-line, purse-seine, set-net, and long-line fishermen in 22 prefectures at 36 ports. Region and gear-based fishing cooperative associations manage fishing activities, and each group differs in its management goals and strategies. In recent years, this has led to conflicts among Bluefin tuna fishermen who target tunas that spawn in the Sea of Japan. Though the formal scientific evidence is incomplete, some groups of fishermen blame the decline in their catch on the purse-seiners for catching too many young tunas, hence causing a decline in domestic tuna stocks. The nature of the problem stems from a lack of consensus among fishermen on the science related to tuna stock management. Furthermore, our preliminary findings indicate that an introduction of Bluefin tuna aquaculture creates a market for live infant Bluefin, which reshapes domestic Bluefin tuna fisheries and their markets.