2012 Field Report: Evaluation of Pinniped Predation on Adult Salmonids and Other Fish in the Bonneville Dam Tailrace, 2012

The U.S. Army Corps of Engineers (USACE) has used surface observations since 2002 to evaluate the seasonal presence, abundance, and predation activities of pinnipeds, including California sea lions (Zalophus californianus), Steller sea lions (Eumetopias jubatus), and Pacific harbor seals (Phoca vitulina) in the Bonneville Dam tailrace (Stansell, 2004; Tackley, et al., 2008; Stansell, et al., 2010). This monitoring program is part of an ongoing effort to understand and manage pinniped predation on salmonids, particularly Endangered Species Act (ESA) listed Columbia River spring Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (O. mykiss) in the tailrace of the dam. The USACE and partnering agencies have used a variety of deterrents and barriers to prevent predation in and around fishways and to deter predation on salmonids and other fish in the tailrace. 2012 NMFS (National Marine Fisheries Service) Submitted Public Domain 1862