I'm gonna have to disagree with that.
With the technology we have (cameras, taxidermy, etc), there's absolutely no reason to keep a trophy fish these days as the replica's are identical and a lot of the time look even better than the actual fish.
What's the point of harvesting a 15lb Walleye anyways? The meat isn't great from a fish that old.
Edit to add: I had a client in 2010 catch a walleye that went just over 10lbs. It was hooked deep and was bleeding pretty badly. He obviously had the option to keep it..and declined, and since I knew there was a good shot at the fish not making it, I decided to not let it go to waste and kept it myself. The meat was JUNK. It was a greyish colour and rubbery.