Some of the dams along the Columbia that have fish ladders offer public viewing areas to watch salmon make their way through the dam, though seeing fish through the window is rare, as some estimate that 90% of the salmon population of the Columbia has been eliminated by the dams. At the McNary Dam, recent research conducted by the Department of Energy to help the salmon has included running sensor-packed rubber fish through the electrical turbine blades, to learn how to design blades that kill fewer fish.