Visual observations of Chinook salmon ascending fish ladders at Bonneville Dam by ecotype (Bright and Tule) and size class (Jack, Stubby, and Adult) conducted during approximately 1-hour counting periods midday from August through October. These counts are used by fisheries managers to break down visual observations of the total number of Chinook throughout the entire day into different management stocks. The information is used to evaluate run sizes relative to pre-season forecasts to align management targets for harvest with conservation objectives. The visual classifications of ecotypes are subject to errors, which can be substantial in some circumstances, such as when the visual characteristics that distinguish the ecotypes are less pronounced. These data are not used in end-of-season calculations of run size and harvest rates but rather are a tool for in-season monitoring of approximate run size.