Turing rocks on a calm morning was always our method of choice and we caught a lot of them. I did try the minnow trap baited with a can of cat food with holes poked in it. I always caught more turning rocks on my way to check the trap than I ever did in the trap. After a few tries with the trap I deemed it a waste of my time. Look for a shallow rocky beach on the lake where you are going to fish then lift stones slowly and catch the crayfish with your hands , my preferred method, or use a small net to catch them. You can't find a better bait for small mouth bass. IMO