Ideal natural stream conditions exist over the greater part of Great Smoky Mountains National Park, and carefully planned management measures are in operation. Fishes taken for sport and food are the eastern brook trout, rainbow trout, smallmouth black bass and rock bass. Rainbow trout are used to fill the gap between the waters capable of supporting eastern brook trout and those in which smallmouth bass are native. Native species are stocked in virgin waters, in research areas, and in streams where rainbow trout are not well established.