I have a place on the Illinois river where I fish, its a man made marina that has never been used. The whole thing is silted in and is about 4-5 foot deep except for the opening that is about 12 foot deep and only 8 yards wide. The current flows in and out, like the tide of the ocean. Last night the shad where all concentrated around the opening and where being sucked in and out of the opening, the whole time the catfish where rolling on top of the water. I assume eating the shad? I was fishing on the bottom with cut bait and stink bait with very limited luck. Would a bobber work in this situation? If so should I use cut bait or live shad? How deep on the bobber? Any help would be great thanks.