This article revisits through a policy analysis the ongoing debate on shrimp farming aquaculture. It describes the changes in policy orientations that have takenplace in recent years, and tries to relate them to the advocacy strategies developed by different networks and policy communities. The analysis reveals in particular the crucial contribution of the 'power of expertise' and shows how it has been instrumentalised by certain advocacy networks to depoliticise the debate. While this has allowed a number of key stakeholders to refocus the debate on technical solutions, it has prevented other groups concerned with more intractable social and political issues from engaging successfully in the policy process, thus leaving the long-term sustainability of aquaculture still a contentious issue.