MIGRATORY BEHAVIOR OF WILD AND FARMED ATLANTIC SALMON (SALMO-SALAR) DURING SPAWNING

Migratory behaviour at spawning of wild and newly-escaped farmed Atlan tic salmon was analysed by radio telemetry in the River Alta, North No rway. Spawning areas were located by aerial surveys. Farmed females mo ved significantly more than wild females (P<0.01). There was no such d ifference between the two groups of males. About 83% of the wild fish stayed within identified spawning areas for 1 day or longer. The corre sponding figure for farmed salmon was only 43% (P<0.05). Wild salmon s tayed 8.1 days inside spawning areas and farmed salmon 5.2 days. The p resent results suggest that escaped farmed salmon had reduced spawning success compared with wild fish.