The Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus) is a subspecies of cutthroat trout native only to the Green and Colorado River basins, which are west of the Continental Divide. Cutthroat trout found in other river basins belong to other subspecies. In the past, this subspecies was found throughout portions of the Colorado River drainage in Wyoming, Colorado, Utah, Arizona, and New Mexico. However, today scientists believe this fish occupies 13% of its historic range