Origins of Spring Chinook Salmon in Clear Creek

Chinook salmon in Clear Creek, a tributary to the upper Sacramento River, were extirpated due to mining activities in that system in the early twentieth century.  Threatened spring Chinook salmon have recently re-colonized Clear Creek, presumably from the two extant populations in the basin: Butte Creek, and Mill-Deer creeks.  We analyzed 96 SNP markers in spring Chinook salmon from Clear Creek and used assignment tests to determine whether they originated from the Butte or Mill-Deer population.  We then used pedigree reconstruction to assess whether or not colonizing individuals from these two populations exhibited assortative mating within Clear Creek.