What non-native fish species poses a threat to Colorado's native trout populations?

The non-native fish species that poses a significant threat to Colorado's native trout populations is the Lake Trout. While Brown Trout and Rainbow Trout are also non-native species in Colorado, the Lake Trout specifically has been known to have detrimental impacts on native trout, particularly in high-altitude lakes. Lake Trout are larger predators and compete directly with native species such as the Colorado River cutthroat trout for resources. This competition, combined with their predatory nature, can lead to declines in native trout populations, as they can overpopulate and disrupt ecological balance in aquatic environments.

In contrast, although Brown Trout and Rainbow Trout are commonly found in Colorado and can impact native species, their effects are generally less severe compared to that of Lake Trout. Brook Trout also pose competition to native species, but the Lake Trout has been identified as a more significant threat because of its predatory behavior and ability to thrive in certain high-elevation environments where native trout once dominated. Understanding the ecological dynamics of these fish species is crucial for the protection and management of Colorado's aquatic ecosystems.