Although the Atlantic salmon is primarily a fresh water fish it spends a big part of its adult life at sea as a fast moving pelagic predator.  During this part of their life-cycle Atlantic salmon swim alongside and share the same ocean environments of commercially-fished species of the pelagic complex such as herring, mackerel and blue whiting. Atlantic salmon is now threatened by problems it’s facing during this ocean migration and international research is becoming more and more focused towards this phase of the salmon life-history profile.  The fishing of salmon at sea has been illegal in Iceland since 1932 and therefore very little is known about the marine life of salmon in Icelandic waters. Sampling salmon at sea using specific cruses is expensive and results are not always predictable. The utilization of the fishing fleet through a surveillance agency was a novel approach and yielded a good sampling coverage regarding both the number of samples and area covered.

The SALSEA-Merge project yielded an extensive genetic database representing ~85% of the non-Baltic European salmon production and this database was used to develop a unique molecular assignment protocol dubbed GRAASP: Genetically-based Regional Assignment of Atlantic Salmon Protocol. The objective of this study was to sample salmon at sea around Iceland; determine age and growth patterns from scales and otholites; and use the newly developed GRASSP to individually assign fish to its population of origin. Preliminary results indicate that the sea south and east of Iceland are much more important than previously thought, especially for salmon originating from UK and Ireland and southern Europe.