Management Strategy Evaluation for the Hilsa (Tenualosa ilisha) Fishery in the Bay of Bengal, Bangladesh

The Hilsa shad, Tenualosa ilisha (Hamilton, 1822) is a national fish of Bangladesh. Overexploitation and the presence of an immature size group have been documented in the catch composition. Some effectively practiced precautionary management measures such as lower catch limit, fishing ban during peak breeding season and juvenile stage have been initiated without considering associated uncertainties. This study attempts to evaluate the existing measures and quantify the management performance for better understanding and implementation of management strategies, with a holistic projection-based management approach like management strategy evaluation (MSE) using a newly developed data-limited management toolkit (DLMtool) for the hilsa fishery in Bangladesh. According to the findings, eight management procedures (MPs) such as AVC_MLL, FMSyref, FMSYref75, FMSYref50, LBSPR, minlenLopt1, matlenlim, and CCI, assessed by DLMtool performed well. Consequently, TAC (Total Allowable Catch) of suggested two MPs indicates a fairly wide difference compared to the hilsa catch in 2022. The engaged fishing mortality in 2022 was almost double than referenced fishing mortality of 0.25, which recommended limiting the fishing effort at a considerable level. The spawning potential ratio (SPR) was calculated as 0.37 and the estimated minimum size of hilsa to capture should be > 28.22 cm TL (Total Length). As a primary study on MSE for hilsa fishery, research in numerous areas, including improvement of overall data collection for populating OM (Operating Model), uncertainty quantification, and model improvement, is still necessary for sustainable management using this holistic approach.