Effects of Stocked Trout, Native Small-bodied Fish, and Winter Surface Aeration on Zooplankton in Small Boreal Foothills Lakes

  • Author / Creator
    Holmes, Teslin G.
  • Trout are commonly stocked into Alberta lakes to enhance angling opportunities. Many of these lakes contain native fish and require aeration to prevent trout winterkill. I assessed effects of trout and native fish on zooplankton abundance, biomass, size, community composition, and vertical distribution among six stocked, five unstocked, and three fishless lakes in the boreal foothills; I also investigated the impact of aeration in a Before-After-Control-Impact study. Stocked trout had limited affects on zooplankton communities and populations in lakes containing native fish, with greater microcrustacean richness and greater abundance of one rotifer species. Fish-bearing lakes (stocked and unstocked), however, differed greatly from fishless systems, with higher abundances of most taxa but smaller cladoceran and calanoid sizes. In fish-bearing lakes, conspicuous zooplankton also demonstrated selection for deeper water. No effect of aeration was detected. Thus, impacts of trout and aeration on zooplankton in boreal foothills lakes containing native fishes appear limited.

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  • Degree
    Master of Science
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    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.