The contribution of Atlantic salmon (Salmo salar L.) enhancement to a sustainable resource

Enhancement methods have been applied for more than a century throughout the natural range of the Atlantic salmon (Salmo salar L.). Hatcheries, the cornerstone of enhancement programmes, are used to: facilitate colonization of new habitats; restore or rehabilitate stocks to once productive habitats; supplement wild stock production; compensate for major environmental disturbances or problems such as hydroelectric development and acid rain; support fisheries entirely dependent upon hatchery stocking; and foster research and technology development. The benefits from enhancement progammes include: contributing to fisheries and wild stock conservation; increased awareness of the resource and natural environment; technology support for the aquaculture industry; and increased knowledge of salmon biology. The risks from enhancement include: reduced genetic diversity and population fitness; adverse ecological effects; and further degradation and loss of wild stocks. Enhancement-is one of a series of management measures that requires careful planning and should be fully integrated within management programmes for the stocks, the resource and its ecosystem. This paper reviews the application of enhancement technology in management programmes for Atlantic salmon in North America and Europe with emphasis on the former. Emphasis is placed on the use of hatcheries because of their prominence as an enhancement tool. (C) 1997 international Council for the Exploration of the Sea.