I don't think the DNR can stop people from cooking fish. I know it's a no no to clean them & pitch the entrils, guts, on the ice or put back in the water. That's a form of littering. One year up the Betsie river , fishing salmon I filleted some on the river. There already was dead salmon floating in the river, & I thought rather then lug these big stringers up a steep hill, clean them right on the river bank. The DNR came down to the river & saw the blood on a dead tree trunk & asked about that. My buddy had already taken the cleaned fish back to the car , so I acted dumb. He said it was illegal to do that. He didn't actually see me do it & he checked our license & left. I thought with hundreds of fish dying in the river , why not just pitch the carcasses. That was michigan, but, I'm sure it's the same in most states.