, Volume 200, Issue 1, pp 593–602 | Cite as

Some positive and negative effects of stocking whitefish on the ecosystem redevelopment of Hjarbæk Fjord, Denmark

  • Knud Rasmussen
Part Eight: Management


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.

Key words

biomanipulation coregonids chironomids zooplankton eutrophication 


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  1. Bay, J., 1986. Fishery biological studies in Hjarbæk Fjord and Lovns Bredning. Report from the Environmental Department, Viborg Amtskommune, 60: 1–35 (in Danish).Google Scholar
  2. Danish Standard, 1986. Danish Standard: DS 221, DS 223, DS 224, DS 292, DS 291, DS 2201. Dansk Standardiseringsråd, Copenhagen, 50 pp.Google Scholar
  3. 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.Google Scholar
  4. Jeppesen, E., M. Søndergaard and H. Rossen, 1989. Restoration of lakes by fish manipulations. Danmarks Miljøundersøgelser, Silkeborg: 1–71 (1) (in Danish).Google Scholar
  5. Lammens, E. H. R. R., 1989. Causes and consequences of the succes of bream in dutch eutrophic lakes. Hydrobiol. Bull. 23: 11–18.CrossRefGoogle Scholar
  6. Lehtonen, H., 1981. Biology and stock assessments of coregonids by the Baltic coast of Finland. Finnish. Fish. Res. 3: 31–83.Google Scholar
  7. Leonhard, S. B. & V. Mahler, 1986. The benthic fauna of Hjarbæk Fjord 1986. Report from the environmental Department, Viborg Amtskommune, 58: 11–72.Google Scholar
  8. 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.Google Scholar
  9. 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.Google Scholar
  10. 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.Google Scholar
  11. 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).Google Scholar
  12. Rasmussen, K., 1979. Studies on the whitefish stock in Ringkøbing Fjord and the River Skjernå. Report from Water Quality Institute 1–61 (In Danish).Google Scholar
  13. Rasmussen, K., 1988. Results of rearing and releasing white-fish in the hypertrophic Hjarbæk Fjord, Denmark. Finnish Fish. Res. 9: 417–424.Google Scholar
  14. Svärdson, G., 1976. Interspecific Population Dominance in Fish Communities of Scandinavian Lakes. Rep. Inst. Freshw. Res., Drottningholm 55: 144–171.Google Scholar

Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • Knud Rasmussen
    • 1
  1. 1.Environmental DepartmentViborg AmtskommuneViborgDenmark

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