Economic instruments offer the potential to reach pre-determined environmental goals at a lower aggregate cost than less incentive-based measures, but administrative underpinnings crucial to the effective functioning of economic instruments may be lacking in developing countries. For this reason, pragmatic analysts and policymakers often advocate the use of so-called ‘mixed’ instruments that combine incentive mechanisms with improved administrative arrangements. This paper explores such possibilities with reference to intensive shrimp aquaculture, which dominates shrimp farming and is an important economic sector in Thailand. This activity has been cited as a major contributor to environmental degradation in Thailand and several other countries through destruction of mangrove forests, salinization of land, sludge disposal, and, in particular, water pollution. An analytical model is presented that highlights some of the key opportunities and limitations of mixed instruments applied to shrimp aquaculture. Mixed instruments are then proposed and evaluated.