Management strategy evaluation for real-time closures in the short mackerel fishery in the Gulf of Thailand

Area and time restrictions are widely used in fisheries management for their simplicity and conservation benefits. Static closures (STCs) often fail to protect migratory fish; therefore, real-time closures (RTCs) are increasingly being adopted. However, RTCs require extensive and rapid data collection and analysis. The vessel monitoring system and daily landing reports provide near real-time data on fishing activities and fish abundance. We conducted a management strategy evaluation of RTCs and STCs in the Gulf of Thailand short mackerel fishery to clarify the efficacy of using RTCs to minimise fishing mortality, while considering their appropriate use with surveillance data for a migratory fish. The results support RTCs as more flexible and requiring a smaller closure area compared with STCs to achieve management objectives. We recommend gathering CPUE data on a monthly basis and using the highest CPUE threshold level to define a closure unit; no unit should be shut down until all units achieve the threshold level. Our results validate the efficacy of the RTC strategy for curtailing fishing mortality of a mobile species and demonstrate the effective use of RTCs to mitigate uncertainty in the migratory patterns of the species in an otherwise unpredictable, fluctuating environment.