Trace element composition of smolt scales from Atlantic salmon (Salmo salar L.), geographic variation between hatcheries

The other elements incorporated in the hydroxyapatite layer (HAP-layer) analysed for this study seems shifted by water treatment done in the hatcheries. Scale chemistry may provide a powerful tool to determine the origin of escaped farmed Atlantic salmon. However, further investigations should be performed before this method can be implemented in the Norwegian salmon management, particularly on two topics. These are the stability of trace elements incorporated in the HAP-layer after change of water environment, and whether the elemental profile from the freshwater hatchery is still recognizable after the salmon has spent more than 2 years in sea.