Fronm looking at it, I rather doubt that it is a kokanee, as kokes are sockeye strain. In the last few months I have caught no less than 2 chinook residuals in the Lake Washington basin, one in Sammamish, and one in Cottage Lake. the one in cottage was the bigger of the two, 14" and fought like a linebacker on my 7 wt fly rod.

I plan only letting a couple of fisheries guys look at the photo, and I bet they will concur with me. Residual Chinook seem to be everywhere right now.