Responses of tuna stocks to temporal closures in the Indian Ocean

Implementing temporal closures is a potential management tool to control the fishing pressure and for stock rebuilding plans. In the Indian Ocean, the yellowfin and bigeye stocks are estimated to be overfished and subject to overfishing, and the Commission has requested to investigate diverse management measures to improve the status of these stocks. In this study, we used the assessment models implemented in Stock Synthesis 3 (SS3) to evaluate the impacts on the future stock status of different closure strategies for yellowfin, bigeye, and skipjack. We found that closing any quarter to all the fisheries would result in stocks not being overfished and not being subject to overfishing by the last year of the projection period. Analyzing fleet-specific closures, we found that closing only the purse seine fishery that uses fish aggregating devices (PS-FAD) would produce the largest positive effect on the stock status compared to the other fisheries. We also compare the status of the stock in the last year of the projection period under the current recommendations for catch reduction.