Genetic Characterization of Adult Chinook Trapped in lower Asotin Creek

The Washington Department of Fish and Wildlife (WDFW) and the National Marine Fisheries Service (NMFS) consider Asotin Creek Spring Chinook to be functionally extirpated because annual redd counts were near zero for many years (Table 1, and Snake River Salmon Recovery Plan â€" Technical Document 2006). In recent years the numbers of adult spring Chinook and redds observed in Asotin Creek have increased to as high as 13 redds per year in 2004. WDFW staff were able to access upstream migrating Chinook at a lower Asotin Creek trap that was operated to sample and enumerate adult steelhead (Mayer et al. 2008). Tissue samples, fish lengths, scales, and tag or mark information were collected from 31 adult or jack Chinook in 2005 and 2007(Table 2). Adult Chinook were sampled during May through early October in 2005, and during May and June in 2007.

Our goal was to determine the likely origin of the adult spring Chinook in Asotin Creek through the use of genetic analyses. This information would then be used to inform management decisions regarding potential reintroduction efforts for spring Chinook in Asotin Creek (either for fisheries enhancement or ESA recovery efforts) and for making funding decisions regarding habitat enhancement projects in Asotin Creek. Funding for genetic analyses was provided by WDFW.