The enrichment of a mesotrophic lake by carbon, phosphorus and nitrogen from the cage aquaculture of rainbow trout, Salmo gairdneri.
The cage aquaculture of rainbow trout, Salmo gairdneri Richardson, enriched the mesotrophic Glebokie Lake in Poland with carbon, phosphorus and nitogen. Two generations were studied, from their introduction to the cages in June until their removal as marketable trout in the autumn of the following year. For every kg of marketable trout produced, the lake was enriched by 0.75 kg C, 0.023 kg P and 0.10 kg N (27.91, 0.84 and 3.58 g/m a year). The eutrophication is expected to cause the loss of the natural populations of Coregonidae. Harvesting trout in summer and autumn does not make full use of the high utilization of food during those periods; it is suggested that harvesting should occur in October and November.