Overwintering Results of Ten Aerated Lakes in the Northwest Boreal Region 2000-2001


David Jackson


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 2000 - 2001 (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. 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 2000 - 2001 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 1999-00).

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