Finding evidence for the impact of incentive-based hilsa fishery management in Bangladesh: combining theory-testing and remote sensing methods.
Hilsa (Tenualosa ilisha) fishery management in Bangladesh is a rare example of ‘carrot-and-stick’ management in developing world fisheries. Impact evaluation traditionally relies on the projection of counterfactuals and so, due to the limited availability of baseline social and ecological data in the hilsa fishery, there has been no rigorous impact evaluation of the management package.
This study uses a theory-based, mixed-methods approach inspired by the principles of process tracing to collect and assess evidence that a) the intended outcomes of management have been realised; and b) management has contributed to these outcomes. It combines statistical analyses of fishers’ knowledge and perceptions with remote sensing data to increase confidence in some components of the hypothesised causal mechanism, and highlight weaknesses in others. Hilsa management appears to have contributed to a socioeconomic improvement, and may have contributed to some increase in hilsa abundance. In particular, radar data provided convincing evidence of compliance with sanctuary fishing bans. However, strong spatial variation in perceptions of trends in and impact of regulations on hilsa indicate that impacts on hilsa abundance could have been undermined by habitat suitability in some areas.