Fish are important to the Y2Y region for ecological, cultural and economic reasons.

They are a prominent food source for grizzly bears and other wildlife, and fish are also a significant food, cultural, and recreational resource for humans.

One hundred and fifty-two fish species have been identified in the region’s 23 major drainage basins. Of those, 104 are (or were) native, and 48 are non-native. Five native species have been extirpated from the area, while two have gone fully extinct.

The northern reaches of Y2Y hold some of the only watersheds left in North America that are free of invasive or exotic fish species. This is significant, as the presence of invasive or exotic species (such as rainbow or brown trout) can disturb the natural balance of the aquatic ecosystem and lead to the decline, and in some cases, the extermination of native species. Y2Y recognizes that non-native trout have an important place in local economies and recreation, and thus does not advocate the removal of game species like rainbows and browns. Instead, we look for ways to improve overall aquatic health and do everything possible to make rivers hospitable to reoccupation by native species like the westslope cutthroat trout and bull trout.