Scientists believe that aquatic invasive species are one of the greatest threats to America’s trout and salmon—in recent years, we’ve seen alarming examples of exotic invaders taking a toll on some of our most iconic waters.

When the Clark Fork River leaves Montana on its westward journey to the Pacific, it is Montana’s largest river—and one of its most storied. Its famous tributaries, like Rock Creek and the Blackfoot and Bitterroot rivers are among the most popualar angling destinations in America.

The Yellowstone is a river of legend, where an angler can cast to rising native trout amid the splendor of the world’s first national park, or hop a ride in a drift boat and cast to wild browns through Montana’s Paradise Valley.