Re-population of stocks by the mass release of fish species into the North Sea is briefly discussed in the light of recent evidence on the behaviour and physiology of artificially cultured populations. The rearing of marine fish, crustaceans and molluscs in the EEC member states is then described with particular reference to the more economically important species. It is considered that, although a number of international and national organisations are already concerned with the practical application of mariculture techniques in Europe, the Community itself has an important part to play in the promotion of marine fish and shellfish rearing, especially in those regions of the EEC where there are few other alternatives for development. © 1979.