On the economics of releasing cultured fish into the aquatic environment

Several factors, including dwindling ocean fish stocks, the high price of wild fish, and the commercial success of enclosed fish farming, have rekindled interest in enhancing natural stocks by the release of artificially raised individuals into the ocean environment. Due to ecosystem interrelationships and constraints, enhancement of fish stocks, irrespective of the purpose, generally has far-reaching biological consequences. Therefore, it almost invariably also has economic and social consequences well beyond those of relevance to the stock enhancers themselves. There are, in other words, external effects associated with ocean stock enhancement. This article is concerned with these problems. It develops a simple theoretical model for investigating the essential external effects of ocean stock enhancement. On the basis of this model, it is demonstrated that a stock enhancement industry will generally not release the correct number of individuals into the ocean. More surprisingly, perhaps, the analysis also shows that if stock enhancement is going on, conventional fishing activity should be modified. The article goes on to discuss institutions and mechanisms that would correct the problem. Theoretically, the appropriate mix of taxes and subsidies could, in principle, do the job. Another, probably more efficient method, consists of the implementation of individual property rights in the form of tradable harvesting and fish release quotas or licenses.