Bird predation on hatchery reared Atlantic salmon smolts, Salmo salar L., released in the River Eira, Norway

Abstract

Carlin-tagged Atlantic salmon smolts have been released in the River Eira in western Norway during the period 1961 - 1980. Just after release birds were observed as smolt predators. Each year the river bank was searched for tags and pellets containing tags. This recovery rate varied between 0.0 - 10.8% in a total of 46 smolt releases during 20 years. Predation of smolts was positively correlated with the water discharge in the river, and negatively correlated with the recapture rate of adult salmon, accounting for 14% of the variation in adult recapture rates.