Feeding and prey‐selection of wild Atlantic salmon post‐smolts

The diet of post‐smolt Atlantic salmonSalmo salarcaught in the Trondheimsfjord and Frohavet in central Norway, based on stomach contents analysis, showed a gradual change during migration from the river to the estuary, fjord and coastal areas. Post‐smolts caught in the estuary had eaten intertidal gammarid amphipods, while post‐smolts caught further seawards preyed upon available marine prey such asCalanusspp., adult euphausiids and fish larvae. The frequency of adult insects was high in all post‐smolt stomachs. The gradual change in diet suggested that feeding conditions in the early marine phase were important for post‐smolt survival and growth. With the exception of the copepods, there was no overall similarity between species composition of the plankton samples and the stomach contents. Although the hypothesis that the post‐smolts are opportunistic feeders cannot be rejected, the composition of the stomach contents suggests a possible selectivity of advantageous prey.