Trout are not native to Arkansas. Arkansas's trout fisheries are the result of cold-water discharge downstream from many U.S. Army Corps of Engineers dams. Before these dams, the White River was full of smallmouth bass and other warmwater fish. The coldwater discharge wiped out the smallmouth fisheries.
The federal government mitigated the damage through the annual stocking of trout, which can handle much colder water temperatures. Brown trout can reproduce successfully in Arkansas, but rainbow trout populations require annual stockings.