Thesis
Movement and distribution of trout following hypolimnetic oxygenation in Twin Lakes, Washington
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/102389
Abstract
Twin Lakes are popular trout fishing lakes on the Colville Confederated Tribes Reservation in Washington. Thermal stratification and hypolimnetic oxygen demand have led to anoxic conditions in the hypolimnion of both lakes, therefore restricting rainbow trout, brook trout and Columbia Basin redband trout to a narrow band of suitable habitat. In North Twin Lake in 2009, a line diffuser hypolimnetic oxygenation system was installed to increase trout habitat. We assessed trout distributions with and without hypolimnetic oxygenation using ultrasonic telemetry, gillnetting, and hydroacoustics in North and South Twin Lakes. Hypolimnetic oxygenation increased minimum usable trout habitat in North Twin from about 8% to 49% of total lake volume. Ultrasonic telemetry observations of redband trout below the average thermocline at a depth of 6 m had a significantly higher percent of total observations during hypolimnetic oxygenation. Furthermore, redband trout swimming speeds were significantly decreased during oxygenation. Gillnets captured high numbers of trout in the metalimnion nets (5 to 8 m) of both lakes. However, significantly more trout were captured in the oxygenated hypolimnion in North Twin Lake. Population estimates based on hydroacoustic soundings showed no significant difference in total numbers of fish in North Twin Lake before versus during oxygenation. However, hydroacoustic data from deep layers was excluded due to large swarms of Chaoborus sp. that obscured fish targets at the available frequencies. Overall, hypolimnetic oxygenation has established a thermal refuge for trout in North Twin Lake. Fishery managers should consider the new productive capacity of trout during hypolimnetic oxygenation when stocking North Twin Lake for a put-grow-take fishery.
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Details
- Title
- Movement and distribution of trout following hypolimnetic oxygenation in Twin Lakes, Washington
- Creators
- Emily M. Clegg
- 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, Washington] :
- Identifiers
- 99900525054501842
- Language
- English
- Resource Type
- Thesis