Deepwater Spawning of Fall Chinook Salmon (Oncorhynchus tshawytscha) near Ives and Pierce Island of the Columbia River, 2004 (Annual Report, 2004-2005)

摘要

Pacific Northwest National Laboratory conducted video-based boat surveys to identify fall Chinook salmon (Oncorhynchus tshawytscha) spawning areas located in deep water (greater than 1 m) downstream of Bonneville Dam in fall 2004. This report documents the number and extent of Chinook salmon spawning near Ives and Pierce Islands of the Columbia River and is the sixth in a series of reports prepared since 1999. The main objectives of this study were to find deepwater spawning locations of fall Chinook salmon in the main Columbia River channel, collect additional data on physical habitat parameters at spawning sites, and provide estimates of adult spawners in the surveyed area. The primary search area was adjacent to the upper portion of Pierce Island, and the secondary search zone was downstream of this area near the lower portion of Pierce Island. A secondary objective was to document the occurrence of any chum salmon (O. keta) redds in the deeper sections downstream of Hamilton Creek (slough zone search area).