The only real way to tell a splake from a coaster brookie is to gut it and count how many pyloric caeca. Those are the small finger like projections of the stomach. Otherwise they can look pretty much like either depending on the environment they are living in. Trout have 23-55, splake 65-85, and lake trout usually have at least 90 and can have up to 200.
Wow ictheology class just came in handy!!!!!!