Using Acoustic Telemetry to Assess Compliance with Biological Opinion Survival Standards at Federally Operated Columbia River Dams

Under the 2008 Federal Columbia River Power System (FCRPS) Biological Opinion (BiOp), dam passage survival should be >0.96 for spring outmigrants of salmonid smolts and >0.93 for summer stocks and estimated with a standard error (SE) <0.015. A virtual/paired release design was used to estimate smolt survival from the face of The Dalles Dam to the boat restriction zone (BRZ) 2 km downstream.  The approach included releases of acoustic-tagged smolts upriver above John Day Dam that contributed to a virtual release downriver at the face of The Dalles Dam.  A survival estimate from this release was adjusted by a paired-release below The Dalles Dam.   A total of 3,880 yearling and 4,449 subyearling Chinook salmon and 3,885 steelhead smolts were tagged and releases in this investigation.  The Juvenile Salmon Acoustic Telemetry System (JSATS) tag, model number ATS-156dB, weighing 0.438 g in air, was used in this investigation.  Dam passage survival for yearling Chinook salmon smolts was estimated to be 0.9641 (SE = 0.0096), 0.9534 (SE = 0.0097) for steelhead, and 0.9404 (SE = 0.0091) for subyearling Chinook salmon smolts in 2010.  The BiOp requires a two-year average at or above the survival standards before compliance has been achieved.