If you're looking for real true Great Lakes Yellow Perch, good luck! What most restaurants are serving as lake perch nowadays is actually a european fish called Zander or a european farm raised version of walleye. There is very limited commercial perch fishing on the great lakes these days, I think mainly only on Lk. Erie.(I may not be 100% correct on this but I know the rest of the great lakes have very limited commercial perch fishing). I know there is one place in Green Bay, Maricque's, that can actually serve real great lakes perch because they were originally a commercial fishing family so they can catch it to serve in their restaurant but not for resale. If you ask at any restaurant what kind of fish they're actually serving they should be able to tell you what it really is. Buyer beware!
If you're an aficionado of REAL perch you'll know what I'm talking about... otherwise, everything else is just another fish fry and you probably won't know the difference...???