Title: Toward optimal use of Bangladesh Hilsa resource: Bioeconomic modelling

The hilsa shad (Tenualosa ilisha) fishery is the largest single species fishery of Bangladesh managed under open access system and was chosen for the study. The purpose of the study was to develop optimal policy to assess the optimal exploitation of the fishery. The objective was to maximize the net benefit of the fishery and rebuilding of hilsa stock. Schafer model was chosen to construct the bioeconomic model and to provide an optimal sustainable fishery. Aggregate harvest and effort data was used. Economic parameter on fishing effort, investment and operation cost was gathered as inputs of the model. Sustainable hilsa fishery model was developed indicating unstable and collapse of the fishery at current effort level. Optimal equilibrium model showed effort can be higher than the sustainable fishery but lower than the biomass. The most efficient effort control time path to traject the fishery to optimal sustainable yield (OSY) by giving the highest present value was calculated showing that moderate adjustment path is more acceptable. The path shows that present value and the sustainable biomass was reasonable within the 20-year management horizon. The path could increase the biomass about 27% and net present value about US $7 billion.