Something to remember about the number of fish passed above the rack is that generally, escapement is determined through spawner surveys. In my experience, surveyors will find maybe a third, or less, of the fish actually there.

On the Cedar, years ago, the escapement estimate for the river was less than the number passed above the rack.

I don't know how WB escapements are done, but I suspect that the number passed above the rack is not used. Meaning that there still may be an issue with the 3-year mean.