Movements of non-maturing cultured Atlantic salmon (Salmo salar) in a Canadian river

High numbers of non-maturing, cultured Atlantic salmon that escaped after one winter in sea-cages ascended into fresh water in the Magaguadavic River, New Brunswick. Acoustic telemetry was used to investigate the movements and behaviour of 14 of these fish in the river over the natural spawning period. Four of the fish remained in deep, slow areas within 1 km of the dam, five moved less than 10 km upstream, and five moved no further than 17.5 km. They then remained at these sites for the rest of the study. Thus, all fish failed to reach the known spawning areas located Further upstream. It is presumed that the limited movement of the cultured fish was related to their Failure to sexually mature. Why these non-maturing salmon entered fresh water remains unanswered, but their residence in the river could have ecological implications. (C) 1997 International Council for the Exploration of the Sea.