Influence of trout farm discharge on the production of two populations o stream-dewlling brown trout (Salmo trutta (L.)) and rainbow trout (Salmo gairdneri (Rich))

Studies on the influence of organic pollution on the production of stream-dwelling brown trout and rainbow trout populations in a Danish medium sized stream, up- and downstream of a trout farm were carried out in the period September 1973 to October 1976 inclusive. The production and energy consumption of the brown trout and rainbow trout populations were estimated. The feeding habits were analyzed and the energy sonsumption was divided on food types. The very high production of brown trout and rainbow trout was restricted to a section immediately below the fish farm and production tn the whole steam increased less. This increased production was mostly made up of rainbow trout.