The contribution of tidal fluvial habitats in the Columbia River Estuary to the recovery of diverse salmon ESUs

1 The contribution of tidal fluvial habitats in the Columbia River Estuary to the recovery of diverse salmon ESUs Curtis Roegner1,Daniel Bottom1, Antonio Baptista2, Lance Campbell3, Andrew Claiborne3,Kurt Fresh1, Susan Hinton1, Regan McNatt1, Charles Simenstad4, David Teel1, Rich Zabel1 Report of research by Fish Ecology and Conservation Biology Divisions Northwest Fisheries Science Center National Marine Fisheries Service National Oceanographic and Atmospheric Administration 2725 Montlake Blvd. E. Seattle, Washington 98112-2097 for Portland District Northwestern Division U.S. Army Corps of Engineers P.O. Box 2946 Portland, Oregon 97208-2946 May 2013 1NOAA Fisheries, Northwest Fisheries Science Center 2Oregon Health and Science University 3School of Aquatic and Fisheries Sciences, University of Washington 4Washington Department of Fish and Wildlife2 INTRODUCTION AND STUDY OBJECTIVES The 2008 Biological Opinion on Operation of the Federal Columbia River Power System established estuary restoration goals for ten-year survival improvements of 9% for ocean-type and 6% for stream-type ESUs. To support these goals, a qualitative assessment process (Columbia River Estuary Recovery Plan Module) was devised to identify limiting factors and to prioritize estuary restoration actions based on their presumed survival benefits. The method ranks the potential benefits of various restoration projects based on published results and professional judgments about their relative effectiveness. Empirical estimates of survival benefits are unavailable, however, and the actual contributions of single or cumulative estuary actions to the survival goals in the Biological Opinion are unknown. Today scores of wetland restoration projects have been undertaken in the estuary as a method to recover at-risk salmon populations throughout the Columbia River basin, based in part on the latest information about the estuary’s role as a productive nursery ground for juvenile salmon (Bottom et al. 2005