by Jim Habera Coldwater Fisheries Biologist Tennessee Wildlife Resources Agency

The American Fisheries Society’s most recent (2004) taxonomic review recognizes 16 species of native trout, salmon, and grayling (members of the family Salmonidae) in North America.  Additionally, several distinct subspecies have been identified, particularly for rainbow and cutthroat trout.  Some regions, such as Alaska and the intermountain western U.S., have a diversity of coldwater habitats and, consequently, may have as many as 10 species and subspecies of these important game fish.  During the late 19^th and most of the 20^th centuries, many salmonids were transplanted outside their original ranges to supplement existing fisheries or create new ones, resulting in the patchwork of native and nonnative populations that we have today.   

The Southeastern US

Currently, most states in the southeastern U.S. have trout fisheries that typically consist of rainbow trout, brown trout (which are native to Europe and western Asia), brook trout, or some combination of these.  A few other species, such as lake trout and cutthroat trout, also provide fisheries in some places and a few others, such as kokanee salmon, have been tried unsuccessfully over the years.  Coldwater habitats managed for trout in the region now include spring fed streams, tailwaters, and some reservoirs.  Historically, however, coldwater habitat supporting native trout was limited to streams in the southern Appalachian Mountains of Virginia, Tennessee, North Carolina, South Carolina, and Georgia.  And the only salmonid inhabiting these streams was the brook trout.

A native southern Appalachian brook trout from Tennessee

But these weren’t (and aren’t) just any brook trout.  Genetic studies over the past decade have shown that brook native to the southern Appalachians (south of the New River in Virginia) are quite distinct from brook trout stocks native to the central Appalachians, New England, or other parts of the species’ native range.  In fact, genetic difference between the brook trout that have been isolated in the southern Appalachians since the end of the last glacial period (10-15 thousand years ago) and other brook trout stocks approaches the level characteristic of subspecies.  Although southern Appalachian fish have not yet been officially recognized as a separate brook trout subspecies (more study is needed), they are the region’s only truly native salmonid and are important parts of its ecological integrity and angling legacy.

Much of the original range of native southern Appalachian brook trout was lost during the early 20^th century through habitat degradation, primarily caused by the poor logging practices of the day.  Rainbow trout (and later, brown trout) were introduced as habitat quality improved and demand for trout fisheries increased.  However, populations of these nonnative fish expanded into waters formerly occupied by brook trout and in some cases displaced existing brook trout populations.  Concern about the loss of native brook trout distribution led to restoration efforts involving stocked brook trout.  Because fishery managers were unaware of the distinctiveness of the native fish, brook trout from northeastern U.S. stocks were used because they were much easier to culture at hatcheries.  These “nonnative” hatchery brook trout were widely stocked for years, resulting in wild brook trout populations consisting of native fish, hatchery descendants, or hybrids. 

Today, wild brook trout inhabit about one-fourth of the coldwater stream habitat in the southern Appalachians.  Just under half of this wild brook trout resource is known to consist of native, southern Appalachian fish and they face ongoing threats, such as habitat loss related to land use changes.  However, natural resource management agencies throughout the region have recently developed and are now implementing new strategies and guidelines aimed at conserving and enhancing the remaining populations of the Southeast’s only truly native salmonid. 

*For more information on native southern Appalachian brook management, see the associated paper from Fisheries.