Overwintering Results of Ten Aerated Lakes in the Northwest Boreal Region 1999-2000
Lake aeration is a fishery enhancement technique that is used to maintain dissolved oxygen levels in eutrophic lakes prone to winterkill. Ten stocked lakes that are susceptible to winterkill were aerated in the 1999-2000 (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, Zama Pond and Cutbank Lake. The lakes ranged in size from 2-172 ha and in depth from 3.0-22.0 m. Cutbank Lake has been added to the aeration program this year (November) and is the largest lake Alberta Conservation Association aerates to date, at 172 hectares. The objective of this project is to annually sustain dissolved oxygen levels in these lakes at or above 3.0 mg/l. Maintaining the dissolved 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 system for aeration on eight of the ten aerated lakes. At Spring Lake a point release system is still operated, to destratify the water column in the fall and a 1/3-hp Gast compressor aerates Zama Pond. The 1999-2000 aeration program results were successful with all ten lakes overwintering.
Previous year(s) over wintering results and aeration methods can be found in the Annual Progress Reports, Alberta Conservation Association, Northwest Boreal Region (1986-87 to 1998-99).