Adaptation of lake-origin burbot stocked into a large river environment
2015
Hardy, Ryan S. | Stephenson, Sarah M. | Neufeld, Matthew D. | Young, Shawn P.
Burbot Lota lota maculosa numbers in Kootenay Lake and Kootenai River of British Columbia, Idaho, and Montana have diminished due to habitat changes from the construction of Libby Dam. Recent implementation of a conservation strategy included aquaculture to supplement the population using a donor stock from a self-sustaining lake population within the watershed. Evaluation of release strategies using telemetry and mark recapture through hoop netting suggests lake-origin Burbot have adapted to the Kootenai system and selected riverine over lacustrine habitat. Previous telemetry work identified good survival and dispersal of released Burbot, and vast dispersal distance and lacustrine use. However, our analysis of a broader telemetry dataset indicated that only 24% of age 1–4 Burbot were detected in the lake. Recapture hoop net data indicated that Burbot residing in the river have growth and survival rates comparable to the historical population. Spawning of hatchery origin fish was detected at historical riverine spawning locations. Other than later spawn timing, our evaluations suggest lake-origin fish are mimicking movement and habitat use of the historical riverine population. This study, in combination with others, provides evidence that Burbot progeny from lacustrine brood stock can successfully survive, grow, disperse, and spawn in a riverine environment.
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