Synchrony in marine growth among Atlantic salmon ( Salmo salar) populations

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Jensen, Arne Johan, Fiske, Peder, Hansen, Lars Petter, Johnsen, Bjørn Ove, Mork, Kjell Arne, Næsje, Tor Fredrik
• Other Authors: Trudel, Marc
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2011
• Subjects: Atlantic salmon; Barents Sea; North Atlantic; North Atlantic oscillation; Norwegian Sea; Salmo salar
• Online Access: http://dx.doi.org/10.1139/f10-156; http://www.nrcresearchpress.com/doi/full-xml/10.1139/F10-156; http://www.nrcresearchpress.com/doi/pdf/10.1139/F10-156

More synchronous growth was observed between close, than more distantly separated populations of Atlantic salmon ( Salmo salar ), during both the first and the second year at sea. The marine growth of seven Norwegian populations, located between 60°N and 70°N, were correlated with sea surface temperatures (SSTs) in the Barents Sea, the Norwegian Sea, and the North Sea, and it was found that growth correlated best with the water temperatures in the area located closest to their home river. Growth was also compared with three broad-scale climate indices (North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation, and subpolar gyre), with the strongest relationship occurring with the NAO index. However, SSTs explained more of the variability than the climatic indices did. Growth increment for the first year, but not the second year, was higher for southern than northern populations, mainly because of later smolt migration to sea in the north, and hence, a shorter growth season. For multi-sea-winter fish, all populations except one had a negative trend in growth with years for both the first and the second year at sea. For the second year at sea, this was most pronounced after the beginning of the 1980s. This is in accordance with the negative trend in pre-fishery abundance of adult salmon during the same period.