VILDFISKENS BET»DELSE FÖR SPRIDNINGEN AV FOSFOR FRÅN FISKODLINGAR / The importance of wild fish to the distribution of phosphorus from fish farms
The hypothesis tested in this work is that there is a significant direct uptake of phosphorus (from faeces from the culrivared fish and feed loss) from fish farms leading to increased growth ofwild fish. Direct uptake (DU) is defined as the phosphorus bound in wild fish. DU is associated with the growth ofall types ofwild fish in relation to the fish farm emissions. It is also referred to as phosphorus in extra fish biomass. To test the hypothesis, an experiment with indicator pamcles was performed in Lake Södra Bullaren, Sweden, which has fish cage farm for rainbow trout (the annual producrion in 1993 was about 500 tons). The results show that wild fish (mainly roach and bream) eat a significant part of the particles, mainly from faeces from the cultivated fish. This consumption then distributes the parricles within the eniire lake. “Complete abstract not presented.”