Stock assessment and management implications of short mackerel (Rastrelliger brachysoma) in the Gulf of Thailand

Abstract

This study is to examine the stock status of short mackerel (Rastrelliger brachysoma) in the Gulf of Thailand, Based on the analysis of population dynamic models, some biological reference points including maximum sustainable yield (MSY), fishing intensity at MSY (fMSY) and acceptable biological catch (ABC) were estimated. The acceptable biological catch (ABC) of the species in 2019 was estimated at 39,772 ton. The exploitation rate (E) was 0.72, which was higher than the optimum value (E = 0.5). The size at first capture was 14.5 cm, while the optimal size was 15 cm. Fcurrent was 4.69 year-1 which was higher than the optimal value (F0.1) based on Yield per recruit analysis. The analysis of spawning biomass per recruit showed that SSBRcurrent was smaller than SSBRoptimal (level of F40%). This study showed that there were not only growth overfishing, but recruitment overfishing for this stock. A number of management strategies and tactics were suggested for the sustainable management of short mackerel in the Gulf of Thailand.