Population dynamics of the data-limited Indonesian shortfin eel (Anguilla bicolor) fisheries in the Greater Sunda Islands

The high demand for eel capture production and aquaculture is dependent on wild-caught juvenile species, posing a significant risk of overfishing and population depletion. This shows the need for effective management strategies to ensure the long-term sustainability of eel fisheries in Indonesia. Therefore, this study aimed to assess population dynamics of the data-limited Indonesian shortfin eel (Anguilla bicolor) in the Greater Sunda Islands. A length-based stock assessment of Anguilla bicolor was conducted in the Kedurang River, Bengkulu, the Serayu River, Central Java, and the Lorog River, Pacitan, East Java, using length frequency data and life history population parameters. The result showed that Anguilla bicolor had an asymptotic length ranging from 90.93–154.88 cm and a constant growth rate of 0.21–0.34 per year. The species was heavily exploited, as showed by current fishing mortality (Fcur = 0.40–1.22 per year), which exceeded natural mortality (M = 0.46–0.56 per year), and the observed optimal fishing mortality (F40% = 0.46–0.69 per year). This study showed that overfishing in the Serayu River was caused by high fishing pressure on Anguilla bicolor. To address the challenge, proposed management efforts should focus on establishing eel conservation areas, maintaining river connectivity by providing fish ladders, implementing restocking programs, enforcing fishing regulations, and enhancing community participation and engagement.