Mike C.
Believe that the lakers were planted in Whatcom (circa 1895) and there were reports of fish being caught through the mid-1940s. Could not find any confirmed reports of lake post 1950 - some large cutts and rainbows but no lakers.

Also were some lakers in Lake Sammamish but they seem to have disappeared in the mid-1960s.

Agree that the char in Cushman were/are bull trout.

Tight lines
S malma