Open Sea Releases of Atlantic Salmon Smolts, Salmo salar, In Central Norway, 1973–83

Low returns of adult Atlantic salmon (Salmo salar) from releases of hatchery-reared smolts initiated experiments to increase recapture rates in the River Surna. A hypothesis that heavy postsmolt mortality due to predation could be reduced by guiding the smolts through coastal areas was tested. Three sites of release were selected: in the Surna, in the fjord, and on the coast off the Surna. Offshore releases gave 111% higher total recapture rates compared with river releases. The remote migration system did not seem to be disturbed by open sea releases, but the number of strayers to rivers other than the Surna increased significantly with the distance between point of release and the native river. Site of release of smolts was more important than genetic background of the fish for the site of recaptures of adult salmon.