Origin, migration and growth of wild and escaped farmed Atlantic salmon, Salmo salar L., in oceanic areas north of the Faroe Islands

We examined the distribution, migration and origin of wild and escaped farmed Atlantic salmon, Salmo salar L., in the northeast Atlantic ocean north of the Faroe Islands based on individual tagging of salmon in this area. Recoveries of wild salmon were reported from homewaters in nine north Atlantic countries, and in a number of different rivers throughout the distribution range of Atlantic salmon. Most tags were recovered in Norway, but relatively large numbers of returns were observed in Scotland and Ireland as well. No fish were recaptured at Faroes. Fish tagged in the autumn tended to return to areas closer to the tagging site than fish tagged in the winter. This strongly suggests that salmon originating from most areas of the distribution range are at some life stage present in this area, but in variable proportions at different times. Most of the salmon returned home to spawn the next autumn, and the fish that stayed for another year originated from northern areas of Europe. All recoveries of farmed salmon were in Norway except one on the west coast of Sweden, suggesting that they could have escaped mainly from Norwegian fish farms. Assessment of the proportion of wild salmon from different countries present north of the Faroe Islands revealed that 40% of the fish were of Norwegian origin, and Scotland and Russia accounted for about 20% each. Four tags of wild fish were reported from Canada, all in the same year they were tagged. This demonstrates that adult Atlantic salmon can cross the north Atlantic ocean in less than 6 months.