I'm actually standing on dry river bottom taking this photo. The river bottom, in these rapids, is shale. When it is wet it is soapstone, slicker than snot. Black and slippery just like soap. I fish just to the left of this photo, but not in the rapids, you'd have to have a 10,000# sinker and the river would still move it. No, you fish in the stillest, deepest water. That's where the fish are. On the bottom. They aren't stupid', it's easier to hang out in the stillest water than fight that current all day. What they eat, great big shiner minnows, actually come to them. The just know where to hang out. This cell phone photo is grainy but in the background is the dam, spillway, and power house. N.P.P.D. operates this hydro electric plant.
These fish, below, are laying on a Formica sink cut out. They would be 4 to 8#'s. Your limit from the Spencer Dam to the Missouri River, is 5 fish per day.