I'm not going to question the size of fish in that river, I've caught some good fish there and have not even been on the best stretch of river. Congratulations ! If you get a chance, for something different, try Mccoys spring creek, outside Dillon. Nice. Do me a favor, if your there long enough, find where Big Sheep Creek is, I believe it is south of town off of I-15, and see how it fishes. Some years back, a local told me about it and said then that it fished good for browns and said I needed to try it. Never got the chance when it was warm enough to try it. Also, Canyon Ferry lake there has rainbows that pull like I would imagine a bison could......strong. Anyway, have fun there.