Food of anadromous brown trout at sea

The food of migratorySalmo truttain coastal marine waters along the Norwegian Skagerrak coast varied significantly with age, season and habitat of the fish. The main prey categories in terms of frequency of occurrence were fishes followed by crustaceans, surface insects and polychaetes. Seasonal variation in diet and within habitats was found, supporting the view that brown trout is an opportunistic feeder. An ontogenetic niche shift was observed with post‐smolts feeding on inshore and shallow water prey communities, while larger brown trout fed mainly on pelagic fishes.