The Fishing Bridge stretch of the Yellowstone River is where Yellowstone Lake's cuththroat trout spawn, and at certain times of year one can see thousands of them from the bridge. Fishing has always been allowed in national parks (but not hunting) and for many years there would be a line of anglers standing shoulder to shoulder on this bridge, hauling them out. This had a predictable impact on the fish population and has been prohibited since 1973.