A study to estimate salmonid survival through the Columbia River estuary using acoustic tags, 2005

In 2005, NOAA Fisheries, with Battelle Pacific Northwest National Laboratory and the U.S. Army Corps of Engineers, initiated the second phase of a multi-year project to estimate juvenile salmonid survival through the lower Columbia River and estuary. A total of 870 yearling and 1,217 subyearling run-of-the-river Chinook salmon Oncohrhynchus tshawytscha tagged with surgically implanted acoustic transmitters and passive integrated transponder (PIT) tags were released through the Bonneville Dam juvenile bypass facility outfall into the Columbia River. Yearling Chinook salmon were released 4 May-1 June (4 releases); subyearling fish were released 18 June-16 July (5 releases). Mean survival, assessed using the single-release estimation model, ranged from 0.564 (SE = 0.0683) to 0.873 (SE = 0.0545) for yearling release groups, and from 0.150 (SE = 0.245) to 0.748 (SE = 0.0497) for subyearling releases. Pooled across all releases, mean survival estimates were 0.754 (SE = 0.1797) for yearling Chinook salmon and 0.653 (SE = 0.2446) for subyearling Chinook salmon. Contract no. E86910060