Have undertaken a new project. If anyone ever trapped snapping turtles and have any tips they could offer up I could sure use them. I have a couple of home-made wire traps and a couple of hoop-net type turtle nets like this.
I never had luck with trapping snappers. We mostly caught cooters and red ears in traps. Grabbing is the way to get a lot of snappers. Just make sure you know which side the head is on before you stick your hand in the hole. You basically walk the marsh and look for bubbles and once you locate the turtles den you plug the entrances and hope you are grabbing at the ass end. That picture you posted appears to be an alligator snapper. If you got that in a trap it is dumb luck because they hunt by waiting for prey to come to them.
Oh I'm catching 10-25 of those red-eared sliders in a trap at times. I've caught snapping turtles by walking in a huge pond that was only a few feet deep. We'd step on them, use one boot to shimmy them up other leg/boot until we could see which end to grab. I'm not going to put my hands on the bottom to feel for them. They can't resist fresh bloody bait. I actually caught him on a line I set. I set a dozen of them with a single hook to see if there were some snappers in the area of a certain bayou I was fishing. They do hunt for food the way you say but they'll also go in traps and bite on baited lines.
You really that bored? Hell I got lots of crap you can do up here instead of wasting your time acting like that croc catcher guy.
It's challenging. I like challenging myself, learning new things. Dude! You've never eaten snapping turtle in a gravy? No better meat. More flavor than guinea.