Bull trout and westslope cutthroat trout, native to the Stehekin River drainage and Lake Chelan, have been severely impacted by non-native fish introductions. Bull trout are currently thought to be extirpated from the Stehekin River and pure native strains of westslope cutthroat in the basin have suffered severe declines. Bull trout, in east-side Cascade streams, were listed as federally endangered during 1998. Westslope cutthroat trout and bull trout in west-side Cascade waters are candidate species for federal listing. The status of certain amphibian populations is also of interest.
Amphibians are an important component of the northwestern fauna.
Twenty-two species inhabit forests of the northwest, with 14 of these species endemic to the region. Many of the habitats that they are associated with are increasingly affected by human activities. Fish stocking, alteration of streams, wetlands, and riparian areas, and logging practices have created widespread impacts to amphibian communities. Several species of frogs have considerably contracted distributions as a result of human disturbances. The spotted frog, cascade frog, and red-legged frog all occur in NOCA and are listed by the State of Washington as threatened species.