This study aimed to evaluate the effectiveness of closed season policy using an integer linear programming, targeting the large purse seine fishery in Korea. In the analysis, based on Cheng and Townsend(1993), fishing effort (fishing days by month) was assumed to be distributed for profit maximization of vessels and catch of immature fish was estimated. The analytical results showed that the effects of closed season policy would vary in accordance with the monthly closures in terms of fishing profits and catch of immature fish. A closed season policy by month had different effects on fishing profits and catch of immature fish by species. It implies the importance of considering seasonal changes of fish species when limiting fishing efforts with the closed season policy.
This study aimed to empirically investigate the applicability of ecosystem-based TAC (Total Allowable Catch) fisheries management targeting the large purse seine fishery where multi-species are regulated by TAC. Using a linear programming, the optimal fishing effort and the catch amount by species which maximize fishing profits were analyzed under the constraint condition of catch limits by species. Analytical results showed that an application of TAC on only chub mackerel would have negative impacts on fish stocks such as hairtail and jack mackerel by increasing the level of fishing effort to achieve its allocated catch limit. However, under the constraint condition of catch limits of all species, it was shown that optimal catches of all species were achieved within their catch limits. It implies the importance of ecosystem-based management considering biological and technical interactions of species those were excluded in the traditional single species fisheries management.