Population Dynamic Parameters and Length Based Spawning Potential Ratio (LB-SPR) of Red Snapper (Lutjanus malabaricus) in The Eastern Java Sea

Abstract

Decision in fisheries management must be made based on the best scientific evidence available. In the poor data fisheries, the fish length data can be useful to determine the status of fish population after its exploitation. The target species of the studied fisheries is the red snapper (Lutjanus malabaricus) in the eastern Java Sea. This study aims to analyze the stock status of red snapper in the eastern Java Sea using Length Based Spawning Potential Ratio (LB-SPR) method. Data collection was done from November 2020 until April 2021. This study separated the analysis of the population dynamic parameters between male and female fish. The growth parameters of male fish was Lt = 92.20 (1 – e−0.27(t-0.07)), with natural mortality (M) of 0.35, fishing mortality (F) of 0.63, and total mortality (Z) of 0.98 per-year. Whereas for female fish, Lt = 91.09 (1 – e−0.29(t-0.44)), with M of 0.38, F of 1.40, and Z of 1.78. The exploitation rate (E) for males was 0.64, and for the female was 0.79. The spawning potential ratio (SPR) was 17%, below the limit reference point of 30% SPR. The current utilization rate of the red snapper in the eastern Java Sea must be reduced to ensure its sustainability.