Observations of abundance, stock composition, body size and food of postsmolts of Atlantic salmon in the NE Atlantic during summer

Abstract

Postsmolt Atlantic salmon were caught during pelagic trawl surveys in the Norwegian Sea in July-August, 1991 and 1995, and off the Hebrides in May-June 1995. Using the swept area technique abundance estimates of postmolts were produced for the three areas, giving estimates of 3,18 million postsmolts within the sampled area of the Norwegian Sea in 1991, 12,89 million postsmolts within the sampled area of the Norwegian Sea in 1995 and 3,26 million postsmolts within the sampled area off the Hebrides in 1995. These figures are rough estimates and should be regarded preliminary. The smolt age distribution of the postsmolts indicated a large component of postsmolts with a southem origin, both of those caught off the Hebrides and in the Norwegian Sea. Only a small fraction of the postsmolts had empty stomachs, indicating a favourable feeding regime in the sampled areas. Parathemisto spp. and 0-group of herring, redfish and blue whiting were the domination food items observed in the stomachs.