The fish are relating to the ledges close to the bottom. The shad are starting to get into a winter pattern going deep sitting out in the channel from one depth all the way to the bottom. When you see this try and target structure in the depth where the top of the shad are sitting (Ex: Shad school from 10ft-bottom, Find structure in 10-14ft). I believe this is where the fish are comfortable because of the temperature. I don't post specific depth because its depends on which areaof the lake you are fishing.