Duckabush Chinook Salmon: 6 Year Review: 2011-2016

This report summarizes the results from the juvenile monitoring study on the Duckabush River from 2011 to 2016. We evaluated freshwater productivity, juvenile outmigration timing, adult abundance and egg to migrant survival of Chinook salmon. Adult Chinook abundance was very low (. 20 adults) across all 6 cohorts in our study. Juvenile abundance was also low, ranging from 686 to 5,221 migrants. The majority of the juvenile captured at the trap were fry sized migrants (<40 mm) and showed very little instream growth following emergence. Parr sized migrants (>40 mm) composed roughly 13 to 38% of the outmigration and ranged in size from 41 to 85 mm. Juvenile outmigration timing was fairly uniform from the middle of January until the trap was removed either in late June or July. Egg to migrant survival varied 25-fold and only two of the five years were within the range of survivals observed at the Green and Skagit Rivers for Chinook salmon. Based on the results of this study, Duckabush Chinook appear to not be meeting the adult abundance criteria listed in the Puget Sound Salmon Recovery Plan.