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Ecosystems

, Volume 4, Issue 4, pp 334–345 | Cite as

The Effects of Stocking and Removal of a Nonnative Salmonid on the Plankton of an Alpine Lake

  • B. R. Parker
  • D. W. Schindler
  • D. B. Donald
  • R. S. Anderson

Abstract

Bighorn Lake, a fishless alpine lake, was stocked with nonnative brook trout, Salvelinus fontinalis, in 1965 and 1966. The newly introduced trout rapidly eliminated the large crustaceans Hesperodiaptomus arcticus and Daphnia middendorffiana from the plankton. In July 1997, we began to remove the fish using gill nets. The population comprised 261 fish that averaged 214 g in wet weight and 273 mm in fork length. Thereafter, zooplankton abundance increased within weeks. Early increases were caused by the maturation of Diacyclops bicuspidatus, few of which reached copepodid stages before the removal of the fish because of fish predation. Daphnia middendorffiana, absent when fish were present, reappeared in 1998. Hesperodiaptomus arcticus, which had been eliminated by the stocked fish, did not return. The proportion of large zooplankton increased after fish removal, but their overall biomass did not change. Algal biomass was low and variable throughout the 1990s and correlated with water temperature but not with nutrient concentrations or grazer densities. Diatoms were the most abundant algal taxon in the lake, followed by Dinophyceae. Chrysophyceans and cryptophyceans were eliminated after the fish were removed. Chlorophyll a concentrations were unaffected. Gill netting is a viable fish eradication technique for smaller (less than 10 ha), shallow (less than 10 m deep) lakes that lack habitable inflows and outflows or other sensitive species. Further work is required to define appropriate removal methods for larger lakes and watersheds.

Key words: trophic cascading; alien species; fish eradication; lake restoration. 

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Copyright information

© Springer-Verlag New York Inc. 2001

Authors and Affiliations

  • B. R. Parker
    • 1
  • D. W. Schindler
    • 1
  • D. B. Donald
    • 2
  • R. S. Anderson
    • 3
  1. 1.Department of Biological Sciences, University of Alberta, Edmonton Alberta, Canada T6G 2E9CA
  2. 2.Environment Canada, Environmental Conservation Branch, Room 300, Park Plaza, 2365 Alberta Street, Regina, Saskatchewan, Canada S4P 4K1; andCA
  3. 3.P.O. Box 127, New Sarepta, Alberta, Canada T0B 3M0CA

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