Appalachian Elktoe in North Carolina

 Alasmidonta raveneliana

FAMILY: Unionidae

STATUS: Endangered, Federal Register, November 23, 1994; Critical Habitat, Federal Register, September 27, 2002

DESCRIPTION: he Appalachian elktoe has a thin, kidney-shaped shell, reaching up to about 10 centimeters (4 inches) (J.A. Fridell, pers. observation 1999). Juveniles generally have a yellowish-brown periostracum (outer shell surface), while the periostracum of the adults is usually dark brown to greenish-black in color. Although rays are prominent on some shells, particularly in the posterior portion of the shell, many individuals have only obscure greenish rays. The shell nacre (inside shell surface) is shiny, often white to bluish-white, changing to a salmon, pinkish, or brownish color in the central and beak cavity portions of the shell; some specimens may be marked with irregular brownish blotches (adapted from Clarke 1981). Clarke (1981) contains a detailed description of the species' shell, with illustrations; Ortmann (1921) discussed soft parts.

RANGE AND POPULATION LEVEL: The Appalachian elktoe is known only from the mountain streams of western North Carolina and eastern Tennessee. Although the complete historical range of the Appalachian elktoe is unknown, available information suggests that the species once lived in the majority of the rivers and larger creeks of the upper Tennessee River system in North Carolina. In Tennessee, the species is known only from its present range in the main stem of the Nolichucky River.

Currently, the Appalachian elktoe has a very fragmented, relict distribution. The species still survives in scattered pockets of suitable habitat in portions of the Little Tennessee River system, Pigeon River system, Mills River, and Little River in North Carolina, and the Nolichucky River system in North Carolina and Tennessee. In the Little Tennessee River system in North Carolina, populations survive in the reach of the main stem of the Little Tennessee River, between the city of Franklin and Fontana Reservoir, in Swain and Macon Counties (DOI, US Fish and Wildlife Service (Service) 1994, 1996, 2002; McGrath 1999; J.A. Fridell, pers. observation 2003), and in scattered reaches of the main stem of the Tuckasegee River in Jackson and Swain Counties (M. Cantrell, Service, pers. comm. 1996; J.A. Fridell, pers. observation 1996, 2002; McGrath 1998), from below the town of Cullowhee downstream to Bryson City. The species has also been recently recorded from the Cheoah River, from the Santeetlah Dam, downstream to its confluence with the Little Tennessee River in the in Graham County (Service 2002).

In the Pigeon River system in North Carolina, a small population of the Appalachian elktoe occurs in small scattered sites in the West Fork Pigeon River and in the main stem of the Pigeon River, above Canton, in Haywood County (J.A. Fridell, pers. observation 1997, 2003; McGrath 1998). The species has been recorded from a single site in the Mills River (upper French Broad River system) in Henderson County (T. Savidge, Catena Group Inc., Raleigh, North Carolina, pers. comm.. 2003); and, the Little River (upper French Broad River system) population of the species, in Transylvania County, North Carolina, is restricted to small scattered pockets of suitable habitat downstream of Cascade Lake (J.A. Fridell, pers. observation 1999, 2003; C. McGrath, North Carolina Wildlife Resources Commission [NCWRC], pers. comm. 2000; Service 2002).

In the Nolichucky River system, the Appalachian elktoe survives in a few scattered areas of suitable habitat in the Toe River, Yancey and Mitchell Counties, North Carolina (Service 1994, 1996, 2002; McGrath 1996, 1999); Cane River, Yancey County, North Carolina (Service 1994, 1996, 2002; McGrath 1997); and the main stem of the Nolichucky River, Yancey and Mitchell Counties, North Carolina, extending downstream to the vicinity of Erwin in Unicoi County, Tennessee (Service 1994, 1996, 2002). Two individuals have also recently been found in the North Toe River, Yancey and Mitchell Counties, North Carolina, below the confluence of Crabtree Creek (McGrath 1999), and 15 live individuals, with no more than 2 to 3 at each site (J.A. Fridell, pers. observation 1998, 2000; Service 2002) and one shell (S. Fraley, Tennessee Valley Authority, Norris, Tennessee, pers. comm. 1999) have been recorded from the South Toe River, Yancey County, North Carolina. The majority of the surviving occurrences of the Appalachian elktoe appear to be small to extremely small and restricted to scattered pockets of suitable habitat.

Historically, the species has been recorded from Tulula Creek (Tennessee River drainage), the main stem of the French Broad River, and the Swannanoa River (French Broad River system) (Clarke 1981), but has apparently been eliminated from these streams (Service 1994, 1996). There is also a historical record of the Appalachian elktoe from the North Fork Holston River in Tennessee (S. S. Haldeman collection); however, this record is believed to represent a mislabeled locality (Gordon 1991). If the historical record for the species in the North Fork Holston River was a good record, the species has apparently been eliminated from this river as well.

HABITAT: The species has been reported from relatively shallow, medium-sized creeks andrivers with cool, clean, well-oxygenated, moderate- to fast-flowing water. The species is most often found in riffles, runs, and shallow flowing pools with stable, relatively silt-free, coarse sand and gravel substrate associated with cobble, boulders, and/or bedrock. Stability of the substrate appears to be critical to the Appalachian elktoe, and the species is seldom found in stream reaches with accumulations of silt or shifting sand, gravel, or cobble. Individuals that have been encountered in these areas are believed to have been scoured out of upstream areas during periods of heavy rain, and have not been found on subsequent surveys (C. McGrath, pers. comm. 1996; J.A. Fridell, pers. observation 1995, 1996, 1999).

REASONS FOR CURRENT STATUS:Available information indicates that several factors adversely affect water and habitat quality of our creeks and rivers and have contributed to the decline and loss of populations of the Appalachian elktoe and threaten the remaining populations. These factors include pollutants in wastewater discharges (sewage treatment plants and industrial discharges); habitat loss and alteration associated with impoundments, channelization, and dredging operations; and the run-off of silt, fertilizers, pesticides, and other pollutants from poorly implemented land-use activities (Service 1994, 1996, 2002).

Freshwater mussels, especially in their early life stages, are extremely sensitive to manypollutants (chlorine, ammonia, heavy metals, high concentrations of nutrients, etc.) commonly found in municipal and industrial wastewater effluents (Havlik and Marking 1987, Goudreau etal. 1988, Keller and Zam 1991). In the early 1900s, Ortmann (1909) noted that the disappearance of mussels is one of the first and most reliable indicators of stream pollution.

Activities such as impoundments, channelization projects, and in-stream dredging operations eliminate mussel habitat. These activities can also alter the quality and stability of the remaining stream reaches by affecting the flow regimes, water velocities, and water temperature and chemistry.

Agriculture (both crop and livestock) and forestry operations, mining activities, highway and road construction, residential and industrial developments, and other construction and land-clearing activities that do not adequately control soil erosion and storm-water run-off contribute excessive amounts of silt, pesticides, fertilizers, heavy metals, and other pollutants. These pollutants suffocate and poison freshwater mussels. The run-off of storm water from cleared areas, roads, rooftops, parking lots, and other developed areas, which is often ditched or piped directly into streams, not only results in stream pollution but also results in increased water volume and velocity during heavy rains. The high volume and velocity cause channel and stream-bank scouring that leads to the degradation and elimination of mussel habitat. Construction and land-clearing operations are particularly detrimental when they result in the alteration of flood plains or the removal of forested stream buffers that ordinarily would help maintain water quality and the stability of stream banks and channels by absorbing, filtering, and slowly releasing rainwater. When storm water run-off increases from land-clearing activities, less water is absorbed to recharge ground water levels. Therefore, flows during dry months can decrease and adversely affect mussels and other aquatic organisms.

MANAGEMENT AND PROTECTION:Assuring the long-term survival of the Appalachian elktoe will require, at a minimum: (1) protecting the existing water and habitat quality of the reaches of the river systems were the species is still surviving and, (2) improving degraded portions of the species habitat within these river systems to allow for the expansion, in numbers and/or range, of the surviving populations where needed for recovery. This will require compliance with existing State and Federal regulations and assistance from the public and local governments and industries in implementing recovery actions.  Also, additional research on the threats to the species, the environmental requirements of the Appalachian elktoe  and fish host(s), and propagation and reintroduction techniques for freshwater mussels is needed.

AUTHOR: John A. Fridell (see address below)

REFERENCES

Clarke, A. H. 1981. The Tribe Alasmidontini (Unionidae: Anodontinae), Part 1: Pegias,Alasmidonta, and Arcidens. Smithsonian Contributions to Zoology, 326:1-101.

Gordon, M. E. 1991. Species account for the Appalachian elktoe (Alasmidonta raveneliana). Unpublished report to The Nature Conservancy. 5 pp.

Department of Interior. U.S. Fish and Wildlife Service. 1994. Endangered and Threatened Wildlife and Plants; Appalachian Elktoe Determined to be an Endangered Species. Federal Register 59(225):60324-60334.

------------- . 1996. Recovery plan for the Appalachian elktoe (Alasmidonta raveneliana) Lea. U.S. Fish and Wildlife Service, Atlanta, Ga. 31 pp.

------------ . 2002. Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Appalachian. Federal Register 67(188):61016-61040.

Goudreau, S. E., R. J. Neves, and R. J. Sheehan. 1988. Effects of sewage treatment plant effluents on mollusks and fish of the Clinch River in Tazewell County, Virginia. Final Rep., U.S. Fish and Wildl. Serv. 128 pp.

Havlik, M. E., and L. L. Marking. 1987. Effects of contaminants on Naiad Mollusks (Unionidae): A Review. U.S. Dept. of Int., Fish and Wildl. Serv., Resource Publ. 164. Washington, D.C. 20 pp.

Keller, A. E., and S. G. Zam. 1991. The acute toxicity of selected metals to the freshwater mussel, Anodonta imbelecilis. Environ. Toxicol. Chem. 10:539-546.

McGrath, C. 1996. Mountain Aquatic Survey. Pages 22 - 26 in Annual Performance ReportVol. V, July 1995 - June 1996, Nongame and Endangered Wildlife Program, North Carolina Wildlife Resources Commission. 185 pp.

------------- 1997. Mountain Aquatic Survey. Pages 14 - 24 in Annual Performance Report Vol.VI, July 1996 - June 1997, Nongame and Endangered Wildlife Program, North Carolina Wildlife Resources Commission. 200 pp.

------------- 1998. Mountain Aquatic Survey. Pages 12 - 16 in Annual Performance Report Vol.VII, July 1997 - June 1998, Nongame and Endangered Wildlife Program, North Carlina Wildlife Resources Commission. 184 pp.

------------- 1999. Mountain Aquatic Survey. Pages 28 - 36 in Annual Performance Report Vol.VIII, July 1998 - June 1999, Nongame and Endangered Wildlife Program, North Carlina Wildlife Resources Commission. 225 pp.

Ortmann, A. E. 1909. The destruction of the freshwater fauna in western Pennsylvania. Proc. of the Amer. Phil. Soc. 48(1):90-110.

------------- 1921. The Anatomy of Certain Mussels from the Upper Tennessee. Nautilus, 34(3):81-91.

For more information please contact:

Mr. John Fridell
U.S. Fish and Wildlife Service
160 Zillicoa Str.
Asheville, North Carolina  28801
Telephone: (828) 258-3939 ext. 225

Species Distribution from known occurrences. Species may occur in similar habitats in other counties.Green counties indicate observed within 20 years. Yellow counties indicate an obscure data reference to the species in the county. Red counties indicate observed more than 20 years ago.

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