We have the native "Mountain Whitefish" in our rivers and streams, and the non-native "Lake Whitefish" in Flathead and other lakes. They were transported to Montana in the early 1900's, from Lake Superior. I have always called them Lake Superior's to help folks understand they are NOT the small mountain whitefish that everyone is more familiar with. And YES, they are delicious!
While we don’t get the big runs every year, our best months for them in the lake are August and September. Mild spring temperatures with little wind usually equates to a good run!