체장 기반 모델을 활용한 대형선망 고등어 어업의 생물경제학적 분석

Abstract

The objective of this study was to assess the stock status of chub mackerel (Scomber japonicus) and to analyze variations in profitability within the large purse seine fishery in relation to changes in size composition. Chub mackerel is a key commercially important species in Korea, with market prices fluctuating based on catch size. For the stock assessment, the Length-Based Spawning Potential Ratio (LBSPR) model was utilized. According to the LBSPR model, the current spawning potential ratio(SPR) of chub mackerel is approximately 0.2, with the length at 50% selectivity(SL50) estimated at about 27.1 cm. Additionally, the population structure across all analyzed years was predominantly composed of individuals smaller than the length at 50% maturity(L50). In light of these findings, a reproductive potential analysis was performed to evaluate the potential consequences of the trend toward smaller size structures. If the existing minimum legal size regulation and the Total Allowable Catch (TAC) system remain unchanged, purse seine fishery profits are projected to decline by 44% over the next decade. Furthermore, the proportion of large-sized chub mackerel is anticipated to decrease from 11% to 4%. Therefore, it is essential to uphold the TAC system while also implementing a size limit regulation for chub mackerel caught by the large purse seine fishery to ensure sustainable resource management.