Assurance Criteria Used in Evaluating the Performance of Survival Compliance Studies at Federally Operated Columbia/Snake River Dams

Dam passage survival must be estimated with a standard error equal to or less than 0.015 for juvenile salmonid survival studies at federally operated hydroprojects on the Columbia/Snake Rivers using acoustic telemetry techniques.  However, the precision requirement specified in the 2008 Biological Opinion is just one of the many criteria that must be fulfilled for a study to be considered valid and representative.  We review the various tests of model assumptions (e.g., downstream mixing, tagger effects, delayed handling mortality, adequate tag life, false positive detections) performed to assure tagging results are reliable.  We also examine the requirements for representative conditions (e.g., fish stocks, size distribution, release locations, dam operations, hydraulic conditions, migrating timing) to assure inferences are realistic and applicable.  The study criteria are illustrated using three years of test data on yearling and subyearling Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) at The Dalles Dam on the Columbia River.