2.1 Sample Collection
Natural-origin steelhead were collected from populations of both the inland and coastal lineages across multipe years from 1996 to 2018 and exhibit a range of migration timing. Samples were collected with a variety of methods, such as electrofishing, smolt traps, and weirs. Non-lethal fin tissue samples and biologically relevant metrics were collected from both smolts and returning adults. Steelhead were collected from locations distributed throughout the Columbia River basin. Sample sizes and coordinates for each collection provided in Figure 1 and Appendix S1 in Table S1.