The main goal of the Asotin Creek Assessment Project is to fully understand the biology of Asotin Creek salmonids, with an emphasis on wild steelhead, which is the focus of this contract for FY09.  Asotin Creek has one of the largest, naturally produced, and self-sustaining populations of wild steelhead in the Interior Columbia Basin – Averaging more than 500 spawning adults and more than 40,000 juveniles in just 46 kilometers, above river kilometer 6.0.  In 2007, the juvenile steelhead population was estimated at greater than 50,375 fish.  The Asotin Creek steelhead population may be at or above Viable Salmonid Population (VSP) thresholds.  

The Asotin Creek Subbasin covers 83,850 hectares in Asotin and Garfield Counties, and includes Asotin Creek, Tenmile Creek, Couse Creek and Alpowa Creek, and their tributaries.  However, the Asotin Creek watershed is comprised of the mainstem of Asotin Creek and its tributaries, including, but not limited to, the North Fork, South Fork, Charlie Creek, and George Creek.  This research, monitoring and evaluation (RM&E) project provides estimates of abundance, productivity, survival rates, and temporal and spatial distribution of ESA-listed Summer steelhead, Oncorhynchus mykiss, in the Asotin Creek watershed.  

This project was implemented in 2004.  Adult salmonids entering Asotin Creek to spawn are enumerated using a resistance board, floating weir.  The juvenile emigrant population is estimated using a rotary screw (smolt) trap.  To date, this project has collected four years of adult data and five years of juvenile data.  The data collected describes a persistent steelhead population, which is variably affected by stray hatchery steelhead, but remains large for a subbasin of its size, when compared to other steelhead populations in the Columbia Basin.  These facts make it a desirable reference/control stream for supplementation effectiveness monitoring of steelhead populations.  

The concept of supplementation has come to the forefront of salmonid conservation in the Columbia Basin.  However, the effects of supplementation are not fully understood, and a significant difficulty in evaluating the effects of supplementation is due to the lack of reference (i.e., control) streams.  Having appropriate reference streams is essential for evaluating the true costs and benefits of supplementation.  Asotin Creek may be the only reference stream that is collecting the wide array of data necessary for supplementation effectiveness monitoring:  A critical unknown in the Columbia Basin.  Therefore, while the project provides population data to monitor adult and juvenile salmonid abundance, we believe its greatest value is as a reference stream.  

Asotin Creek is a scientifically sound reference stream and - given the lack of unsupplemented reference streams for supplementation effectiveness monitoring - is one of the few steelhead populations that can provide reference data for understanding wild steelhead biology.  Using the Asotin Creek Assessment Project to provide reference data for evaluating the effects of supplementation as a recovery tool in the Columbia Basin is supported by the co-managers and associated fisheries management agencies:  NOAA Fisheries, Snake River Salmon Recovery Board, WDFW, the Nez Perce Tribe, ODFW, Wells Hatchery Committee, and the Washington State Governors' Salmon Recovery Office.  This project is also recommended for funding in the 2008 FCRPS Biological Opinion.

Note:  The State of Washington Governor’s Salmon Recovery Office (GRSO) designated Asotin Creek as an Intensively Monitored Watershed (IMW).  This designation was part of the "Comprehensive Monitoring Strategy and Action Plan for Watershed Health and Salmon Recovery" for Washington State, which created intensively monitored watersheds to determine the response of salmon to habitat restoration efforts.  The GRSO is providing roughly $89,540 (no overhead; 42% cost share) to this project in FY09, which will be used to cover some of the costs for work similar to what is described in this SOW.