People have been watching and counting fish on the Columbia River since the completion of Bonneville Dam in 1938. Daytime fish counts are taken by fish counters looking directly into the fish ladders (4 a.m. - 8 p.m.) from April 1 - October 31 each year. From November 1 to February 28, video counts will only be taken at the Bonneville, Lower Monumental and Lower Granite dams. In spring, video counts will only be taken at the Bonneville and Lower Granite dams.
The fish counters take separate counts of adult chinook, jack chinook, clipped steelhead, unclipped steelhead, adult coho, jack coho, sockeye, chum, pink, shad, and lamprey. Adult and jack chinook day counts are added together to get "All Chinook." Clipped and unclipped steelhead day counts are added together to get "All Steelhead." Adult and jack coho day counts are added together to get "All Coho". When fish counts are taken at night (8 p.m. - 4 a.m.) or in the winter (Nov. 1 - March 31), the fish counters use video, recording and reading the entire 60 minutes of each hour, so no estimation is needed.
Counting schedules, which fish species are counted, how counts are reported, and expansion or estimation methods are overseen by the Fish Passage and Operations Management committee (comprised of NOAA, CRITFC, ODFW, WDFW, IDFG, BPA, and Corps of Engineers biologists).