judging by his hand holding the fishes tail, I would say it is about 32 inches
measure the fish in the pic, it is 8 1/2 inches, now measure his fingers holding the tail measure 1 inch, that would be 8 1/2 hands, now consider his fingers to be 4 inches wide and 4 times 8 1/2 equals about 34 inches for the length of the fish.
a very nice walleye indeed.