Hawk, Here's a shot in the dark...By any chance do they release any triploid fish in the area that you were fishing. Triploid fish are fish that have been sterilized through a heat shocking technique. I read the other day that they did stock some in the Great lakes but I can't recall where. I don't know if this technique causes anything like you saw but it obviously messes up the reproductive system as triploid fish attain exceptional size without the maturation of the reproductive systems hence no active spawning but I guess some of them have been observed in streams.
I guess the way to rule this theory out would be to ask if the fish had any mature eggs or sperm.


Duke