Overwintering Results of Nine Aerated Lakes in the Northwest Boreal Region 1998-1999


David Jackson


Lake aeration is a fishery enhancement technique that is used to maintain dissolved oxygen levels in eutrophic lakes prone to winterkill. Nine stocked lakes that are susceptible to winterkill were aerated in the 1998-1999 (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, Swan Lake and Zama Pond. The lakes ranged in size from 2-140 ha and in depth from 3.0-22.0 m. Swan Lake has been added to the aeration program this year and is the largest lake the Alberta Conservation Association aerates to date, at 140 hectares. 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). The Northwest Boreal Region is now using mechanical surface aeration as the main aeration system. Spring Lake is the only lake where the point release system is still operated, to destratify the water column in the fall. The 1998-1999 aeration program results were successful with all nine lakes overwintering.

Previous year(s) over wintering results and aeration methods can be found in Overwintering Results of Nine Aerated Lakes in the Northwest Boreal Region annual reports, Alberta Conservation Association, Northwest Boreal Region (1986-87 to 1997-98).

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