I'm not convinced. When you hold a fish out towards the camera the picture always inflates the size of your hands/fingers, especially with a wide-angle lense like your typical phone camera. Often that's the dead givaway that the fish isn't as big as your immediate reaction is to think. Here, look at me shamelessly trying to make a little smallie look like a wall-hanger:
http://i1026.photobucket.com/albums/...9D6F745E56.jpg
Here it's easier to tell it's just this effect in play because you can see my arms all the way from shoulder to wrist, but if you were to just compare the size of my hands/fingers to my upper arms, there's at least as much inflation as in Roper's pic.
And I don't buy that it's a mount. I don't know too much about taxidermy but I don't think walleye skin is elastic enough to make that eye bulge out of a normal fish. It also looks like he's holding back the anal fin with his index finger which I don't think you could do on a mount. And look at the shine on the skin, especially below the rear dorsal fin... I suppose a mount could have that but it's not typical.
And though I've never heard of belly tickling before, I do find dorsal fins tend to fan out when a fish is being held out of water, it's after they're killed that the fins usually fold in flat.
Of course any type of photo edit is possible but I'm tempted to believe this is real.