Overwintering Results of Eight Aerated Lakes in the Northwest Boreal Region 1996-1997


David Jackson


Lake aeration is a fishery enhancement technique that is used to maintain dissolved oxygen levels in eutrophic lakes prone to winterkill. Eight stocked lakes that are susceptible to winterkill were aerated in the 1996-1997 (October - April) in the Northwest Boreal Region. These lakes were Cecil Thompson Park Pond, Moonshine Lake, Cummings Lake, Sulphur Lake, Spring Lake, East Dollar Lake, Figure Eight Lake, and Zama Pond. The lakes ranged in size from 2.0-53.0 ha and in depth from 3.0-22.0 m. The objective of this project is to sustain dissolved oxygen levels in these lakes at or above 3.0 mg/l. Maintaining the oxygen at this level or higher ensures the survival of trout throughout the winter (Fast 1994). Presently, the Northwest Boreal region is using a point release system of aeration, with mechanical surface aerators being tested on five of the above lakes in the 1996-1997 aeration season. The lakes that were used for conducting the tests were Cecil Thompson Park Pond, Cummings Lake, Moonshine Lake, Sulphur Lake and East Dollar Lake. Theron Miller, a PhD. student at the University of Alberta, is comparing the point release system that the Natural Resources Service now uses to the mechanical surface aerator. Some of the parameters measured were costs (initial, repair and maintenance) and how efficiently these two systems aerate (size of motor to lake and resulting oxygen levels). This is the third and final year in which comparison experiments will be conducted. Details and results from these studies will be in Miller's final report. The 1996-1997 aeration program results were successful with all eight lakes overwintering.

Previous over wintering results and aeration technique comparisons to the 1996-1997 aeration year can be found in Overwintering Results of Nine Aerated Lakes in the Northwest Boreal Region 1995-1996 annual report by David Jackson, June 1997, Natural Resources Service, Northwest Boreal Region.

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