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.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bay, J., 1986. Fishery biological studies in Hjarbæk Fjord and Lovns Bredning. Report from the Environmental Department, Viborg Amtskommune, 60: 1–35 (in Danish).
Danish Standard, 1986. Danish Standard: DS 221, DS 223, DS 224, DS 292, DS 291, DS 2201. Dansk Standardiseringsråd, Copenhagen, 50 pp.
Healey, M. C., 1975. Dynamics of exploited whitefish populations and their management with special reference to the North-West Territories. J. Fish. Res. Bd Can. 32: 427–448.
Jeppesen, E., M. Søndergaard and H. Rossen, 1989. Restoration of lakes by fish manipulations. Danmarks Miljøundersøgelser, Silkeborg: 1–71 (1) (in Danish).
Lammens, E. H. R. R., 1989. Causes and consequences of the succes of bream in dutch eutrophic lakes. Hydrobiol. Bull. 23: 11–18.
Lehtonen, H., 1981. Biology and stock assessments of coregonids by the Baltic coast of Finland. Finnish. Fish. Res. 3: 31–83.
Leonhard, S. B. & V. Mahler, 1986. The benthic fauna of Hjarbæk Fjord 1986. Report from the environmental Department, Viborg Amtskommune, 58: 11–72.
Lindegaard, C. & E. Jónsson, 1983. Succession of Chironomidae (Diptera) in Hjarbæk Fjord, Denmark, during a period with change from brackish water to freshwater. Mem. Am. ent. Soc. 34: 169–185.
Lindegaard & E. Jónsson, 1987. Abundance, population dynamics and high production of Chironomidae (Diptera) in Hjarbæk Fjord, Denmark, during a period of eutrophication. Ent. scand. Suppl., 29: 293–302.
Olrik, K., S. Lundøer & K. Rasmussen, 1984. Interactions between phytoplankton, zooplankton and fish in the nutrient rich shallow lake Hjarbæk Fjord, Denmark. Int. Revue ges. Hydrobiol. 69 (3): 389–405.
Olrik, K., A. Nauwerck, A. Sørensen, H. M. Sørensen & S. Lundøer, 1986. Phyto- og zooplankton in Hjarbæk Fjord 1981, 1984, 1985 og April–July 1986. Report from the Environmental Department, Viborg Amtskommune, 57: 1–71. (in Danish).
Rasmussen, K., 1979. Studies on the whitefish stock in Ringkøbing Fjord and the River Skjernå. Report from Water Quality Institute 1–61 (In Danish).
Rasmussen, K., 1988. Results of rearing and releasing white-fish in the hypertrophic Hjarbæk Fjord, Denmark. Finnish Fish. Res. 9: 417–424.
Svärdson, G., 1976. Interspecific Population Dominance in Fish Communities of Scandinavian Lakes. Rep. Inst. Freshw. Res., Drottningholm 55: 144–171.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
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
Issue Date:
DOI: https://doi.org/10.1007/BF02530376