Abstract
In 1984 the County of Viborg introduced a large-scale programme to improve the water quality in Hjarbæk Fjord, a freshwater fjord cut off from the sea in 1964. Measures were taken to reduce the discharges of nutrients from various sources. To reduce the nuisance of chironomids a large release of whitefish (Coregonus lavaretus L.) was incorporated in the programme. The effects of these efforts on the fish, benthos and plankton communities were studied during a period of five years. The whitefish established a self-reproducing population with a very good growth rate, and may have created quantitative and qualitative changes in the plankton community. Observed changes in the benthos community may also be related to predation by whitefish. The study did not confirm that whitefish could actually control the population of chironomids and diminish, thus, the nuisance caused by them. The stocking of whitefish created an exploitable fish stock of a valuable fish species in the hypertrophic Hjarbæk Fjord.
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Rasmussen, K. Some positive and negative effects of stocking whitefish on the ecosystem redevelopment of Hjarbæk Fjord, Denmark. Hydrobiologia 200, 593–602 (1990). https://doi.org/10.1007/BF02530376
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DOI: https://doi.org/10.1007/BF02530376