Alternative outcomes under different fisheries management policies: A bioeconomic analysis of Japanese fisheries

Abstract

Japanese fisheries are underperforming, with stock declines in some key domestic fisheries. This study examines tradeoffs between allowing current fishing mortality levels to continue versus adopting fishing mortality levels that are intended to maximize either yield or profitability in Japanese fisheries. Because stock status estimates exist for only 37 stocks in Japan, a data-limited model is used to estimate the maximum sustainable yield-based (MSY) reference points for 95 commercially exploited fish stocks using landing data from 1964 to 2015, representing 84% of Japanese landings. Future catch, biomass, and profits are simulated under two policy scenarios: (1) catch at MSY and (2) an economically optimal policy that seeks to maximize profits given the biomass level projected in each year. These scenarios were compared to a business-as-usual scenario in which current fishing mortality rates are maintained into the future. The results suggest that adopting an economically optimal fishery policy could reduce catches over the next two decades, but increase the total annual profits by 3.5-fold and biomass levels by 30% by 2065 compared with the business-as-usual scenario. In comparison, managing for MSY would require less of a short-term decrease in catch, but ultimately result in much lower profits. While these simulations do not account for real-world constraints that may limit implementation of these alternative policies, this analysis is important because it illustrates the tradeoffs and potential fishery upsides possible through fishery management reforms.