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Conservation value of alternative life-history tactics in steelhead trout (Oncorhynchus mykiss)

Posted on:2006-03-23Degree:M.ScType:Thesis
University:University of Toronto (Canada)Candidate:Walters, Joshua ClydeFull Text:PDF
GTID:2453390005996558Subject:Biology
Abstract/Summary:
Salmonid conservation programs typically include captive breeding, fishery regulation and habitat enhancement. This research addresses the consequences of these programs for the demography, ecology, life-history, genetics, and phenotypes of steelhead trout (Oncorhynchus mykiss) in the Keogh River, British Columbia.; The conservation program altered life-history by producing resident hatchery fish, which altered ecology by consuming resources and conspecifics. Residents had phenotypes that diverged from the wild type, and potentially altered genetics and demography by participating in both wild and hatchery anadromous matings.; Two possible negative consequences are an increase in density-dependent competition in the freshwater environment, and a decrease in marine survival due to phenotypic change. Positive outcomes are an increase in total males spawning and thus increased genetic diversity, decreased genetic drift, decreased inbreeding due to breeding across age cohorts, and increased gene flow between hatchery and wild fish. The net effect for conservation remains to be determined.
Keywords/Search Tags:Conservation, Life-history
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