Anadromous brown trout and Atlantic salmon in the Aurland watercourse

Abstract

The river Aurlandselva has been famous for its anadromous brown trout sport fishery, in particular because of the large size of the trout. Atlantic salmon has also been an attractive species. After the hydropower development, the catches of both species declined considerably, and harvesting of salmon has therefore been banned since 1989. This has taken place despite the hydropower company being enjoined to stock the river with 30 000 trout smolts and 10 000 salmon smolts annually. Because of low temperature and a short growth season the growth increment of presmolts is low, and mean smolt age and length of trout are 3.7 yrs and 142 mm, respectively, which is the same as the values before the hydropower development. The mean growth increment for the first summer at sea has declined, while the corresponding growth for the second and third summers at sea remains unaltered.