Recreational and professional fisheries related to freshwater aquaculture

Many professional and recreational freshwater fisheries in Europe benefit from stock enhancement programme which consist in stocking riverside, lakes, and reservoirs with hatchery-reared fish (at least 45 species or sub-species, indigenous or exotic). Stocking aims at diverse objectives, from private commercial ranching to nature conservation. Stocking methodology and effectiveness are extremely variable depending on the species, the water body, and the purpose of stocking. Specific constraints to stocking aquaculture are related to the necessity of producing fish of high biological quality (genetically, behaviourally) which are able to settle efficiently in the wild (and with no risks of sanitary and/or genetic contamination of the native stocks) and/or to allow a high percentage of return as fishery yield. Furthermore, fish cultists involved in stocking aquaculkture have to cope with problems of transport of live fish and of controlling the technology of release in the wild. In this paper we briefly review some of those practices and problems, focusing on a few well documented cases. As a conclusion, we identify three main axes for future development in this developing sector of stocking aquaculture : improving the productivity without impairing the biological and ecological quality of the fish, increasing the number of reared species (diversification) , and taking the opportunity of rearing high-tech products such as sterile fish or strains able to live in modified environments.