Sustainability of Skipjack Tuna in FMA 714, Indonesia: A Five-Decade Analysis of Biological Trends

Skipjack tuna (Katsuwonus pelamis) is a crucial species in global fisheries, particularly in Indonesia’s Fisheries Management Area (FMA) 714. This study examined trends in the biological aspects of skipjack tuna from 1969 to 2024, utilizing a combination of historical data (1969–2018) and quantitative analysis of longitudinal data (2019–2024). A total of 24,618 fork length measurements were analyzed using FISAT II software. The results reveal significant shifts in population dynamics driven by increasing fishing pressure. The dominant size range declined from 35–56cm (1969–1990) to 20–40cm (2001–2010), with juveniles comprising 69.9% of catches by 2019–2024, indicating a high proportion of immature individuals. Recruitment peaks shifted earlier (June–September by 2019–2024), reflecting fishing pressures. Growth parameters showed a marginal increase in asymptotic length (L∞:76.75cm) but slower growth rates (K:0.56 year⁻¹), suggesting population stress. Mortality analysis revealed high exploitation (E:0.59), with fishing mortality (F:1.42) surpassing natural mortality (M:0.97). While recent management measures have stabilized some trends, persistent challenges remain due to elevated juvenile catches and high total mortality (Z:2.39 year⁻¹). To ensure long-term sustainability, adaptive management strategies are essential, including reducing fishing pressure, protecting juvenile stocks, and implementing science-based policies to rebuild the skipjack tuna populations and enhance their resilience.