Nonnatal Stream use by Juvenile Salmonids in the Lower Tanana River 2021-2.pdf

Abstract: In July 2016, we explored 19 nonnatal Tanana River tributary streams between the confluence of the Tanana and Chena rivers for the presence of juvenile Chinook Salmon Oncorhynchus tshawytscha. Only 8 of 19 streams were sampled because the remaining 11 streams consisted of inadequate rearing habitat. The eight streams were sampled 1 km upstream of the tributary and Tanana River interface. Average minnow trap hours per stream was 204 (range 118–230). Despite extensive sampling efforts, no juvenile Chinook Salmon were captured. Instead, we captured juvenile Longnose Sucker Catastomus catostomus (n = 3), Northern Pike Esox lucius (n = 3), and Coho Salmon O. kisutch (n = 2) in minnow traps in two of the eight sampled streams. We used single nucleotide polymorphism analysis of anal fin tissue and epidermal mucus swab samples to confirm field identification for captured Coho Salmon. Although juvenile Chinook Salmon rearing habitat in sampled portions of the eight streams was suboptimal, we recommend temporal sampling upper reaches of larger tributaries to the lower Tanana River to determine rearing habitat use.