Thesis
Changes in salmonid vertical distribution following hypolimnetic oxygenation in North Twin Lake, Washington
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/101952
Abstract
In many lakes, hypolimnetic anoxia and warm surface temperatures during summer stratification can significantly reduce cold-water fish habitat. The resulting “habitat squeeze” can increase fish stress and susceptibility to infection, reduce growth rates, and can cause summer mortality. Such a reduction in optimal habitat has been noted in North and South Twin Lakes in northeastern Washington. In 2008, a diffused line oxygenation system was installed in North Twin Lake to eliminate hypolimnetic anoxia and enhance cold-water salmonid habitat. The system was operational during summer stratification season in 2009 and 2010. We evaluated post-oxygen temperature and dissolved oxygen (DO) in North Twin; South Twin provided an un-oxygenated “reference.” Biologic responses, including changes in Chaoborus distribution and salmonid habitat utilization were evaluated. Habitat usage was estimated using a combination of archival tags, gillnetting, and hydroacoustic methods. The oxygen system eliminated summer hypolimnetic anoxia in North Twin for 2009 and 2010. Archival tag results (p = 0.0308) indicated increased use of the hypolimnion by salmonids in North Twin during oxygenation. Gillnetting and hydroacoustic analysis also revealed salmonids occupying deeper depths in North Twin during summer stratification. More Chaoborus were found in the benthic sediments (p = 0.022) and less in the water column (p = 0.035) of oxygenated North Twin compared to un-oxygenated South Twin. This change indicated that Chaoborus in North Twin Lake potentially exhibit altered diel migration patterns in response to increased salmonid presence and predation in the hypolimnion. Increased use of hypolimnetic cold-water habitat demonstrated that salmonids utilize the hypolimnion when oxygenated.
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Details
- Title
- Changes in salmonid vertical distribution following hypolimnetic oxygenation in North Twin Lake, Washington
- Creators
- Brian P. Lanouette
- Contributors
- Barry C. Moore (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Agricultural, Human, and Natural Resource Sciences, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525123501842
- Language
- English
- Resource Type
- Thesis