Sample collection & genetic analysis
In 2016, a total of 1,520 upstream-migrating adult Yellowstone Cutthroat Trout and 2,925 fry were sampled for genetic tissue. Overall genotype success rates were very high, with 99.9% of adult samples (1,518) and 99.7% of the juvenile samples (2,917) successfully amplifying at 50% or more of the SNP marker panel. Searches for duplicate genotypes identified a total of 15 adult samples which were near exact matches (>95% similar) of another sample, which likely represented adults that passed above the weir, fell back, and were sampled again when they reascended the weir. Duplicate searches among offspring identified seven samples that were a duplicate of another. For both adults and offspring, only one genotype was retained from each pair of duplicates, whichever was the most complete (i.e., had the largest number of alleles called). Parentage analysis assigned 2,310 (78.7% of total number) of the fry samples to a parent-pair handled at the weir.