2021 Pilchuck River Spawner Surveys FY 2020

The project consisted of monitoring the return of chinook and coho salmon in 2021 to stream reaches on the Pilchuck River above the former location of the City of Snohomish Pilchuck River Diversion Dam which was removed in the summer of 2020. Six surveys were completed between September 8th and October 13th. Weekly surveys were supposed to continue until December, however, persistent high river flows prevented staff from being able to safely and effectively conduct the surveys. The sampling that did occur consisted of escapement monitoring including visual live/dead, carcass, and redd surveys. Work occurred from the location of the former dam upstream approximately six miles where Boulder Creek flows into the Pilchuck River. The Tribal staff took scale, otolith, and DNA samples from carcasses will can be used to provide additional information about Chinook and coho salmon age, life history type and river of origin and contribution to the recovery of the Snohomish River Basin chinook population. This project only supported the collection of tissue and DNA samples, the analysis of these collections will occur with non-project funds.

The Pilchuck River is identified as a high priority watershed for the recovery of salmonids in the Snohomish River watershed. The Pilchuck River was historically a major chinook salmon producer, and is important for the maintenance and restoration of the diversity and spatial structure of the Skykomish Chinook population (SBSRTC, 2004). The Pilchuck is also an important steelhead river with a proposed demographically independent winter-run that is managed as a distinct stock by Washington State co-managers based on geographic isolation and age structure (NOAA 2011; WDF, WDW and WWTT 1993). Chinook, steelhead and other salmonid populations are currently only a fraction of their historic abundance within the Pilchuck and the larger Snohomish watershed. With the removal of the City of Snohomish Pilchuck River Diversion Dam chinook, coho, steelhead and other salmon can know access 37 miles of river habitat above the dam. The purpose of the project is to assess the contribution of newly opened up spawning habitat to the Snohomish River Basin chinook population, specifically to determine how many spawning salmon and redds are present in the 37 miles of river previously inaccessible to salmon, how this contributes to the salmon recovery efforts and the overall Snohomish River Chinook, Coho, and Steelhead populations.