Graduation Date
Summer 2020
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Fisheries
Committee Chair Name
Dr. Andrew Kinziger
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Dr. Darren Ward
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Dr. David Hankin
Third Committee Member Affiliation
HSU Faculty or Staff
Subject Categories
Fisheries
Abstract
Distinct populations of steelhead in the wild are in decline. The propagation of steelhead in hatcheries has been used to boost population numbers for recreational fisheries and for use in conservation. However, hatchery breeding practices of steelhead can result in changes in genetic structure. I investigated the genetic structure of winter-run steelhead (Oncorhynchus mykiss) returning to the Mad River, California, where a hatchery has been used enhance production for recreational fisheries since 1971. Genetic variability in Mad River steelhead was evaluated using 96 single nucleotide polymorphisms (SNPs) among 4203 individuals, including the Mad River and nearby locations, and spanning 44 years from 1973 to 2017. I resolved evidence that in the 1970s the Mad River contained both an indigenous population, and a population influenced by the introduction of Eel River winter-run broodstock. Even with the introduction of Eel River broodstock, contemporary Mad River steelhead (1983-2017) appear to be distinct from Eel River collections, as well as other surrounding collections (except Redwood Creek). This distinction is a consequence of the presence of a historically unique population in the Mad River, combined with the inability of the initially introduced Eel River steelhead broodstock to establish itself. Lastly, I found that contemporary Mad River Hatchery broodstock are composed of three groups (or broodlines), defined by adult return year (1) 2009, 2012, and 2015, (2) 2010, 2013, and 2016, and (3) 2011 and 2014. Grouping in 3-year intervals is hypothesized to be a result of the predominant usage of age-3 individuals as broodstock at Mad River Hatchery.
Citation Style
American Fisheries Society
Recommended Citation
Fong, Steven R., "Spatial and temporal genetic structure of winter-run steelhead (Oncorhynchus mykiss) returning to the Mad River, California" (2020). Cal Poly Humboldt theses and projects. 403.
https://digitalcommons.humboldt.edu/etd/403
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