Thesis
The influence of Hypolimnetic oxygenation on diet in a mixed cold- and warmwater fish community in mesotrophic Twin Lakes, WA
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/101453
Abstract
Line-diffuser hypolimnetic oxygenation (HO) was initiated in North Twin Lake, WA (NT) in 2009 to mitigate loss of coldwater fishery habitat due to temperature/dissolved oxygen squeeze and to reduce internal phosphorus cycling. Active tracking, net-captures, and hydroacoustic analyses demonstrated that trout populations rapidly expanded into increased hypolimnetic habitat in the first few years of oxygenation. However, long-term fishery benefits and many basic ecological aspects of hypolimnetic oxygenation have yet to be established. Diet and food web analyses indicate significant changes in feeding ecology of principal fish species in NT 2012, compared to pre-oxygenation (2005) and to un-oxygenated South Twin (ST) in 2012. Rainbow trout (Oncorhynchus mykiss) in NT consumed significantly more large-bodied daphnia during midsummer 2012 than those in ST, where rainbow trout fed primarily on littoral amphipods. Additionally, relative gut weight for brook trout (Salvelinus fontinalis) in August 2012 was significantly higher in NT, compared to ST, apparently due to increased access to hypolimnetic zooplankton. Golden shiner (Notemigonus crysoleucas) diets also appear to include v more zooplankton in oxygenated NT. Littoral-focused largemouth bass (Micropterus salmoides) diets appear not to be altered by hypolimnetic oxygenation. Observed changes in feeding ecology following HO have significant implications for future fishery management in the Twin Lakes.
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Details
- Title
- The influence of Hypolimnetic oxygenation on diet in a mixed cold- and warmwater fish community in mesotrophic Twin Lakes, WA
- Creators
- Megan Maria Skinner
- Contributors
- Barry C. Moore (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525173301842
- Language
- English
- Resource Type
- Thesis