Multigeneration Pedigrees to Monitor Hatchery Broodstock Composition and Genetic Variation of Spring/Summer Chinook Salmon in the Columbia River Basin

Hatchery production of Chinook Salmon Oncorhynchus tshawytscha in the Columbia River basin comprises most anadromous salmonid this region. facilities and programs serve to mitigate for impacts salmonids due construction operation hydropower dams habitat from development addition conservation restoration natural populations. A genetic method referred as parentage-based tagging (PBT) enables highly reliable detection hatchery-origin fish inference multigeneration pedigrees. This study compiles 11 years PBT data nearly 125,000 interior stream-type 24 spawning hatcheries located on tributaries mid- upper Salmon, Clearwater, Grande Ronde subbasins. Multigenerational pedigrees allowed investigation proportions natural- broodstock (pNOB pHOB, respectively) each hatchery enumeration scale between segregated integrated programs. We then compared how pHOB influenced number stray observed, diversity, relatedness, age-class compositions within broodstocks. Over 91.0% could be assigned back their parents, overall less than 1.0% consisted that were unintentionally incorporated into nonnatal evaluated with 0.0–10.0% pNOB, 9 intermediate (10.1–50.0% pNOB), 3 (>50.0% pNOB). There was no correlation or pNOB level but size increased, so did effective breeders. demonstrates utility a monitoring tool broodstocks, results suggest have tradeoffs generally align intended management purpose providing harvest and/or supplementation reintroduction.