Epioblasma capsaeformis - (I. Lea, 1834)
Oyster Mussel
Synonym(s): Dysnomia capsaeformis (I. Lea, 1834)
Taxonomic Status: Accepted
Related ITIS Name(s): Epioblasma capsaeformis (I. Lea, 1834) (TSN 80306)
Unique Identifier: ELEMENT_GLOBAL.2.118984
Element Code: IMBIV16040
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Unionidae Epioblasma
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Concept Reference
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Concept Reference: Turgeon, D.D., J.F. Quinn, Jr., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, R.J. Neves, C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F.G. Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.
Concept Reference Code: B98TUR01EHUS
Name Used in Concept Reference: Epioblasma capsaeformis
Taxonomic Comments: There is a problem related to misidentification and priority concerning Epioblasma and Plagiola. Epioblasma is used in anticipation of a decision in its favor by the ICZN. It has been suggested that this species may be a senior synonym of Epioblasma florentina walkeri (see Buhay et al., 2002), but molecular, morphological, and life history data from Jones (2004) and Jones et al. (2006) suggest they are distinct. Based on molecular, morphological, and life history data, the population from the Duck River, Tennessee, is tentatively proposed as a separate species from Epioblasma capsaeformis populations in the Clinch River because of distinctiveness of molecular genetic markers, differences in mantle pad coloration and texture, greater height of marsupial expansion of the female shell, smaller glochidial size, differing host fish specificity, and behavioral differences in movement of micro-lures (Jones, 2004; Jones et al., 2006).
Conservation Status
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NatureServe Status

Global Status: G1
Global Status Last Reviewed: 23Dec2011
Global Status Last Changed: 28Oct2003
Rounded Global Status: G1 - Critically Imperiled
Reasons: This species has declined (> 80%) to a few disjunct occurrences from what was a much more widespread historic distribution. Populations are disjunctly distributed in nine tributaries and it is rare at these localities with evidence of decline. One population is threatened by dam construction. There is potential for discovery of new populations
Nation: United States
National Status: N1 (15Dec1998)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (SX), Georgia (SX), Kentucky (S1), Tennessee (S1), Virginia (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LE, XN: Listed endangered, nonessential experimental population (10Jan1997)
Comments on USESA: Listed Endangered throughout its range, except in the free-flowing reach of the Tennessee River from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir and the lower 5 RM of all tributaries to this reach in Colbert and Lauderdale Counties, Alabama. Here it is listed as an experimental, non-essential population (Federal Register, 14 June 2001).

The USFWS, in cooperation with the State of Tennessee and Conservation Fisheries, Inc., announced a final rule to reintroduce this species into its historical habitat in the free-flowing reach of the French Broad River below Douglas Dam to its confluence with the Holston River, Knox County Tennessee, and in the free-flowing reach of the Holston River below Cherokee Dam to its confluence with the French Broad River (Federal Register, 12 September 2007). The proposed rule for this action was published on June 13, 2006.

U.S. Fish & Wildlife Service Lead Region: R4 - Southeast
IUCN Red List Category: EN - Endangered
American Fisheries Society Status: Endangered (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 250-1000 square km (about 100-400 square miles)
Range Extent Comments: Historically, this species was distributed throughout the Cumberlandian region of the Tennessee and Cumberland river drainages in Alabama, Georgia, Kentucky, North Carolina, Tennessee, and Virginia in 82 localities (USFWS, 2003; 2004). Currently, in the Cumberland River drainage, remnant populations are found in Buck Creek and the Big South Fork Cumberland River in Kentucky and Tennessee. In the Tennessee River drainage, remnant populations are scattered through sections of the upper Clinch and Powell rivers in Tennessee and Virginia, and the Duck River in Tennessee. Although it has not been seen in recent years in the lower Nolichucky and Little Pigeon rivers in Tennessee it may still persist in low numbers (USFWS, 1997). It is believed to be extirpated from Alabama and potentially from Copper Creek in Virginia (Fraley and Ahlstedt, 1999; Mirarchi et al., 2004). All former Georgia records are believed to be extirpated (J. Wisniewski, GA NHP, pers. comm., January 2007). In Alabama, t historically occurred in Tennessee River downstream to Muscle Shoals and in the Paint Rock and Elk Rivers but naturally occurring populations not reported there since impoundment; plans for reintroduction underway (Mirarchi et al., 2004; Mirarchi, 2004; USFWS, 2004). Records of Epioblasma capsaeformis for North Carolina (Ortmann, 1914) have been shown to be misidentified Epiblasma florentina walkeri (J. Ratcliffe, NC NHP, pers. comm., 2007).

Area of Occupancy: 126-2,500 4-km2 grid cells
Area of Occupancy Comments: Recently, critical habitat was designated for the Duck River (74 river km occupied, 0 river km unoccupied habitat) in Tennessee, Bear Creek (0 river km occupied, 43 river km unoccupied habitat) in Alabama and Mississippi, Powell River (0 river km occupied, 154 river km unoccupied habitat) in Tennessee and Virginia, Clinch River (242 river km occupied, 0 river km unoccupied habitat) in Tennessee and Virginia, Copper Creek (0 river km occupied, 21 river km unoccupied habitat) in Virginia, Nolichucky River (8 river km occupied, 0 river km unoccupied habitat) in Tennessee, Big South Fork (0 river km occupied, 43 river km unoccupied habitat) in Tennessee and Kentucky, and Buck Creek (0 river km occupied, 58 river km unoccupied habitat) in Kentucky (USFWS, 2004).

Number of Occurrences: 1 - 20
Number of Occurrences Comments: Post-1985 records are in nine tributaries, some of these occurrences (Clinch and Duck Rivers and the Big South Fork Cumberland River) are relatively healthy (USFWS, 1998; Jones, 2004). Populations remain in isolated stretches of the Big South Fork (Scott County, Tennessee, and McCreary County, Kentucky) although the identity of these populations may be in question (USFWS, 2003; 2004). Populations are also extant in the Tennessee River system in the Clinch River (Russell and Scott Counties, Virginia and Hancock County, Tennessee), Powell River (Lee County, Virginia), North Fork Holston River (Scott County, Virginia- reintroduced), Nolichucky River (Cocke and Hamblen Counties, Tennessee), and Duck River (Maurey and Marshall Counties, Tennessee); while it may still be extant in Copper Creek (Jones et al., 2001; USFWS, 2003; 2004). Based on molecular, morphological, and life history data, the population from the Duck River, Tennessee, is tentatively proposed as a separate species from Epioblasma capsaeformis populations in the Clinch River because of distinctiveness of molecular genetic markers, differences in mantle pad coloration and texture, greater height of marsupial expansion of the female shell, smaller glochidial size, differing host fish specificity, and behavioral differences in movement of micro-lures (Jones, 2004; Jones et al., 2006).

Population Size: 1000 - 2500 individuals
Population Size Comments: Population size is difficult to estimate, but TVA qualitative surveys and quantitative estimates of density have been very low and continue to decline. A study by Ahlstedt and Tuberville (1997) found densities of 0.76 and 0.22 per square foot in the Powell River in 1979 and 1983, respectively, but absent in 1988 and 1994 (over 14-16 sites sampled), and in the Clinch River found densities of 3.24, 0.11, and 2.92 per square foot in 1979, 1988, and 1994, respectively (over 11-14 sites).

Number of Occurrences with Good Viability/Integrity: Few (4-12)
Viability/Integrity Comments: Barr et al. (1994) determined (based on 1981 survey data) that viable populations exist in the Clinch, Duck, Powell Rivers, and Copper Creek. Populations with good viability can be found in the Clinch River (Virginia and Tennessee) (Jones, 2004), Duck River (Maurey and Marshall Counties, Tennessee) [note this is likely a distinct undescribed species- see Jones et al., 2006), and Big South Fork (Scott County, Tennessee and McCreary County, Kentucky) (USFWS, 2003; 2004). It is rare in the Nolichucky River, Tennessee; but the Powell River, Tennessee, population has not yielded live specimens since the early 1990s (Jones, 2004).

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: Much of the information below is derived from and expanded upon in USFWS (2004):
The greatest threat to this species in the Cumberlandian Region is habitat alteration. Principal causes include impoundments, channelization, pollution, and sedimentation that have altered or eliminated those habitats that are essential to the long-term viability of many riverine mussel populations. Impoundments result in the elimination of riffle and shoal habitats, disruption of a river's ecological processes (flooding, loss of bottom stability, bank sloughing), elimination of current and the covering of rocky and sand substrates by fine sediments, and alteration of downstream water quality and riverine habitat. Daily discharge fluctuations, bank sloughing, seasonal oxygen deficiencies, cold-water releases, turbulence, high silt loads, and altered host fish distribution have contributed to limited mussel recruitment and skewed demographics. Impoundments, as barriers to dispersal, contribute to the loss of local populations by blocking postextirpation recolonization. Population losses due to impoundments have probably contributed more to the decline of the Cumberlandian combshell, oyster mussel, and rough rabbitsfoot and most other Cumberlandian Region mussels than any other single factor (as the Cumberland elktoe and purple bean generally inhabit smaller rivers, impoundments have had less of an impact on them, although the impact is still significant).

Dredging and channelization activities have profoundly altered riverine habitats nationwide, with effects on streams. Channel construction for navigation has been shown to increase flood heights thus exacerbating flood events that convey to streams large quantities of sediment with adsorbed contaminants; and channel maintenance may also result in downstream impacts. The entire length of the Tennessee River and much of the Cumberland River is maintained as a navigation channel with a series of locks and dams--nine on the Tennessee River and four on the Cumberland River. Channel maintenance activities continue to cause substrate instability and alteration in these rivers and may serve to diminish what habitat remains for the recovery of riverine species.

Heavy metal-rich drainage from coal mining and associated sedimentation have adversely impacted many stream reaches, destroying mussel beds and preventing natural recolonization. Acid mine runoff may be having local impacts on the recruitment of, particularly, the Cumberland elktoe, since most of its range is within watersheds where coal mining is still occurring. Impacts associated with coal mining activities have particularly altered upper Cumberland River system streams with diverse historical mussel faunas and have been implicated in the decline of Epioblasma species, especially in the Big South Fork. Strip mining continues to threaten mussels in coal field drainages of the Cumberland Plateau with increased sedimentation loads and acid mine drainage, including Cumberland elktoe and Cumberlandian combshell populations. The Marsh Creek population of the Cumberland elktoe has also been adversely affected and is still threatened by potential spills from oil exploration activities. Coal mining activities also occur in portions of the upper Powell and Clinch River systems, primarily in Virginia. Polycyclic aromatic compounds (PAHs) are indicative of coal fines in the bottom sediments of streams. Known to be toxic to mussels and fishes, PAHs have been found at relatively high levels in the upper portions of the Clinch and Powell Rivers in Virginia.

In-stream gravel mining has been implicated in the destruction of mussel populations. Negative impacts include riparian forest clearing (e.g., mine site establishment, access roads, lowered floodplain water table); stream channel modifications (e.g., geomorphic instability, altered habitat, disrupted flow patterns [including lowered elevation of stream flow], sediment transport); water quality modifications (e.g., increased turbidity, reduced light penetration, increased temperature); macroinvertebrate population changes (e.g., elimination, habitat disruption, increased sedimentation); and changes in fish populations (e.g., impacts to spawning and nursery habitat, food web disruptions). Gravel mining activities threaten the Cumberlandian combshell populations in the Powell River and in Buck Creek, the latter stream representing one of only two remaining populations of this species in the entire Cumberland River system. Mining activities on the Elk River may have played a role in the extirpation of the oyster mussel and Cumberlandian combshell from that river.

Contaminants contained in point and nonpoint discharges can degrade water and substrate quality and adversely impact, if not destroy, mussel populations. Although chemical spills and other point sources (e.g., ditch, swale, artificial channel, drainage pipe) of contaminants may directly result in mussel mortality, widespread decreases in density and diversity may result, in part, from the subtle, pervasive effects of chronic low-level contamination. Mussels appear to be among the most intolerant organisms to heavy metals, several of which are lethal, even at relatively low levels. Among other pollutants, ammonia has been shown to be lethal to mussels. Common contaminants associated with households and urban areas, particularly those from industrial and municipal effluents, may include heavy metals, ammonia, chlorine, phosphorus, and numerous organic compounds. Nonpoint-source runoff from urban areas tends to have the highest levels of many pollutants, such as phosphorus and ammonia, when compared to other catchments. Agricultural sources of chemical contaminants are considerable and include two broad categories--nutrients and pesticides. Nutrient enrichment generally occurs as a result of runoff from livestock farms and feedlots and from fertilizers used on row crops. Pesticides, primarily from row crops, are a major source of agricultural contaminants. Pesticide runoff that commonly ends up in streams may have effects (based on studies with laboratory-tested mussels) that are particularly profound.

Numerous Cumberlandian Region streams have experienced mussel kills from toxic chemical spills and other causes. The high number of jeopardized species in the upper Tennessee River system make accidental spills a particular concern to conservationists and resource managers.

Sedimentation, including siltation runoff, has been implicated as the number one factor in water quality impairment in the United States. Specific biological impacts on mussels from excessive sediment include reduced feeding and respiratory efficiency from clogged gills, disrupted metabolic processes, reduced growth rates, increased substrate instability, limited burrowing activity, and physical smothering. Host fish/mussel interactions may be indirectly impacted by changes in stream sediment regimes through three mechanisms: fish abundance, diversity, and reproduction reduced; impedes host fish attractant mechanisms; interfere with the ability of some species' adhesive conglutinates to adhere to rock particles. Waterborne sediment is produced by the erosion of stream banks, channels, plowed fields, unpaved roads, roadside ditches, upland gullies, and other soil disturbance sites. Agricultural activities produce the most significant amount of sediment that enters streams. Silvicultural sedimentation impacts are more the result of logging roads than the actual harvesting of timber.

Developmental activities associated with urbanization (e.g., highways, building construction, infrastructure creation, recreational facilities) may contribute significant amounts of sediment and other pollutants in quantities that may be detrimental to stream habitats. With development, watersheds become more impervious, resulting in increased storm-water runoff into streams and a doubling in annual flow rates in completely urbanized streams. Impervious surfaces may reduce sediment input into streams but result in channel instability by accelerating storm-water runoff, which increases bank erosion and bed scouring. Although not mentioned specifically, this effect could be increased with projected climate change models. Water withdrawals for agricultural irrigation and municipal and industrial water supplies are an increasing concern for all aquatic resources and are directly correlated with expanding human populations. This impact has the potential to be a particular problem for the Cumberland elktoe population in the Big South Fork system and the oyster mussel population in the Duck River.

The alien Asian clam (Corbicula fluminea) was first reported from the Cumberlandian Region around 1959. This species has been implicated as a competitor with native mussels for resources such as food, nutrients, and space, particularly as juveniles. Densities of Asian clams are sometimes heavy in Cumberlandian Region streams, making competition with populations of some of these five species likely. Paradoxically, large, seemingly healthy, populations of unionids may coexist with Asian clams. The invasion of the nonnative zebra mussel (Dreissena polymorpha) poses a threat to the mussel fauna of the Cumberlandian Region. Although zebra mussels are now in the Tennessee and Cumberland River systems, the extent to which they will impact native mussels is unknown. However, as zebra mussels are likely to reach higher densities in the main stems, large tributaries, and below infested reservoirs, native mussels in these areas will likely be more heavily impacted than mussels in smaller streams without upstream reservoirs. Mussel extinctions are expected as a result of the continued spread of zebra mussels in the Eastern United States. Other potential threats from alien species on native mussels include the black carp (Mylopharyngodon piceus), a native of China. If these species invade Cumberlandian Region streams, they could wreak havoc on already stressed native mussel populations. The round goby (Neogobius melanostomus) is another alien invader fish species released in the 1980s into the Great Lakes in ballast waters originating in southeastern Europe. The arrival of round gobies may therefore have important indirect effects on unionid communities through negative impacts to their host fishes.

Exploitation is considered a very minor, albeit historic, threat due to historical harvesting by Native Americans for food and jewelry, and later by North Americans for pearls, pearl buttons, and cultured pearls. Similarly, information on predation and parasitism could potentially be a threat but there is no supporting information thus far although the muskrat (Ondatra zibethicus) has long been recognized in the literature as a significant mussel predator.

The overall threat to this species, posed by piscine and invertebrate predators, in most instances is not thought to be significant. Although parasitism is not thought to be a significant problem in mussels, excessive trematode infestations in their gonads have been implicated in inducing mussel senescence. The harvest of Cumberlandian Region mussel species for commercial purposes is well documented (Anthony and Downing, 2001). It is doubtful, however, that this species has ever been overly exploited for pearling, pearl buttons, cultured pearls, or any other exploitative activity (USFWS, 2004).

Short-term Trend: Decline of >70%
Short-term Trend Comments: This species was once a commonly found species (1970's), but abundance has dropped and it has been extirpated from many former sites including the mainstems of the Cumberland and Tennessee Rivers now only extant in a handful of stream and river reaches in four states in the Tennessee and Cumberland River systems (USFWS, 1998; 2003; 2004). This represents an approximate 80% reduction in range. The most recent Alabama records are from the Estill Fork of the Paint Rock River in 1980 but it historically occurred in the Tennessee River across northern Alabama and some tributaries (Williams et al., 2008). It is historically (1980) known from Copper Creek (Upper Clinch) in Virginia (Hanlon et al., 2009).

Long-term Trend: Decline of >70%
Long-term Trend Comments: It was historically in the Paint Rock (Jackson Co.) River in northern Alabama (Isom and Yokley, 1973); and upper Elk River, Tennessee (Isom et al., 1973). Dennis (1987) demonstrated a dramatic change in populations in the upper Clinch River at Kyles Ford, Hancock Co., Tennessee, showing a decline from being a dominant species in 1973-1976 to a very scarce species in 1986; and futher documented similar decline at Pendleton Island, Clinch River, in southwestern Virginia (Dennis, 1989). It was historically known from the French Broad River in Buncombe Co., North Carolina, but has since been extirpated from the state (Bogan, 2002). Jones (2004) speculated that the Clinch River form of this species was once widely distributed throughout the Tennessee River system in Virginia, Tennessee, and northern Alabama, and in the Cumberland River system in Kentucky and Tennessee. All former Georgia records are believed to be extirpated (J. Wisniewski, GA NHP, pers. comm., January 2007).

Intrinsic Vulnerability: Highly to moderately vulnerable.
Intrinsic Vulnerability Comments: Without the level of genetic interchange these species experienced historically, many small and isolated populations that are now comprised predominantly of adult specimens may be slowly dying out due to various factors. This may, in part, account for the relatively recent demise of numerous tributary populations. Even given the improbable absence of the impacts from current and existing threats, smaller isolated populations of this species may be lost to the devastating consequences of below-threshold effective population size (EPS). Once-sizable populations of many Cumberlandian mussel species occurred throughout significant portions of the main stems of the large rivers and tributary systems comprising the Cumberlandian Region. This was particularly true for the Cumberlandian combshell and oyster mussel. Historically, there were no natural absolute barriers to genetic interchange among their tributary subpopulations and those of their host fishes (with the notable exception of Cumberland Falls. Without the level of genetic interchange these species experienced historically (because of anthropogenic threats), many small and isolated populations that are now comprised predominantly of adult specimens may be slowly dying out due to various factors (USFWS, 2004).

Environmental Specificity: Moderate. Generalist or community with some key requirements scarce.

Other NatureServe Conservation Status Information

Inventory Needs: Determine the extent of existing populations and continue searching for new EOs.

Protection Needs: All populations should receive protection through aquisition, easement, registry, and working with local, state, and federal government agencies on issues relating to development, water quality, river designations, etc. In particular, management procedures and regulations to control pollution and siltation from upstream areas of the watershed are critical. Critical habitat proposed (USFWS, 2003; 2004).

Distribution
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Global Range: (250-1000 square km (about 100-400 square miles)) Historically, this species was distributed throughout the Cumberlandian region of the Tennessee and Cumberland river drainages in Alabama, Georgia, Kentucky, North Carolina, Tennessee, and Virginia in 82 localities (USFWS, 2003; 2004). Currently, in the Cumberland River drainage, remnant populations are found in Buck Creek and the Big South Fork Cumberland River in Kentucky and Tennessee. In the Tennessee River drainage, remnant populations are scattered through sections of the upper Clinch and Powell rivers in Tennessee and Virginia, and the Duck River in Tennessee. Although it has not been seen in recent years in the lower Nolichucky and Little Pigeon rivers in Tennessee it may still persist in low numbers (USFWS, 1997). It is believed to be extirpated from Alabama and potentially from Copper Creek in Virginia (Fraley and Ahlstedt, 1999; Mirarchi et al., 2004). All former Georgia records are believed to be extirpated (J. Wisniewski, GA NHP, pers. comm., January 2007). In Alabama, t historically occurred in Tennessee River downstream to Muscle Shoals and in the Paint Rock and Elk Rivers but naturally occurring populations not reported there since impoundment; plans for reintroduction underway (Mirarchi et al., 2004; Mirarchi, 2004; USFWS, 2004). Records of Epioblasma capsaeformis for North Carolina (Ortmann, 1914) have been shown to be misidentified Epiblasma florentina walkeri (J. Ratcliffe, NC NHP, pers. comm., 2007).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: endemic to a single nation

U.S. & Canada State/Province Distribution
United States ALextirpated, GAextirpated, KY, TN, VA

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AL Colbert (01033), Lauderdale (01077)
KY Cumberland (21057)*, Laurel (21125)*, McCreary (21147), Pulaski (21199)*, Russell (21207)*, Wayne (21231)*, Whitley (21235)*
TN Blount (47009)*, Claiborne (47025), Cocke (47029), DeKalb (47041)*, Greene (47059), Hamblen (47063), Hancock (47067), Marshall (47117), Maury (47119), Putnam (47141)*, Sequatchie (47153)*, Sevier (47155)*, Smith (47159)*
VA Lee (51105), Russell (51167)*, Scott (51169), Tazewell (51185), Washington (51191)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
05 Licking (05100101)*, Upper Cumberland (05130101)+*, Rockcastle (05130102)+*, Upper Cumberland-Lake Cumberland (05130103)+, South Fork Cumberland (05130104)+, Obey (05130105)*, Upper Cumberland-Cordell Hull (05130106)*, Caney (05130108)+*, Lower Cumberland-Old Hickory Lake (05130201)*, Lower Cumberland-Sycamore (05130202)*, Stones (05130203)*, Harpeth (05130204)*, Lower Cumberland (05130205)*, Red (05130206)*
06 North Fork Holston (06010101)+, South Fork Holston (06010102)*, Upper French Broad (06010105)*, Pigeon (06010106)*, Lower French Broad (06010107)+*, Nolichucky (06010108)+, Watts Bar Lake (06010201)+*, Lower Little Tennessee (06010204)*, Upper Clinch (06010205)+, Powell (06010206)+, Lower Clinch (06010207)*, Middle Tennessee-Chickamauga (06020001)*, Sequatchie (06020004)+*, Guntersville Lake (06030001)*, Wheeler Lake (06030002)*, Upper Elk (06030003)*, Lower Elk (06030004)*, Pickwick Lake (06030005)+, Bear (06030006)*, Upper Duck (06040002)+, Lower Duck (06040003)+, Buffalo (06040004)*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A freshwater mussel that has a yellowish to green colored shell with numerous dark rays.
General Description: Shell medium-sized, elliptical (male) to irregularly obovate (female), slightly inflated, subsolid to quite thin posteriorly (female); anterior regularly rounded; ventral margin slightly curved (male) to almost straight (female); posterior margin obliquely sloped from an obtusely angular posterio-dorsal junction to a blunt or biangulate point at the posterio-ventral junction; posterio-ventral are of female broadly expanded to accomodate the branchial marsupia, slightly inflated, demarcated by sulci, margin may be dentate, expansion may appear bilobed in old individuals; dorsal margin rather straight; beaks broad, elevated above hinge line, sculpted by feeble undulations; posterior ridge angular and more-or-less double (male) to slight or imperceptible (female), a slight sulcus occurs anteriorly in male; periostracum dull to subshiny, yellowish to green with numerous dark green rays across surface, marsupial expansion usually dark green to blackish. Pseudocardinals rather heavy, triangular, double in left valve, single in right; interdentum slight, rather short; lateral teeth slightly curved, rather short, double in left, single in right; beak cavity shallow; anterior muscle scars well-impressed, posterior muscle scars shallow; pallial line impressed anteriorly; nacre whitish to bluish-white.
Diagnostic Characteristics: The pronounced development of the posterio-ventral region in females distinguishes EPIOBLASMA from similarly shaped species. Epioblasma capsaeformis is recognizable by the typically dark coloration and fragility of the marsupial expansion and the lack of development of the posterior ridge (e.g., not angular, no knobs). Males in comparison to similar Epioblasma tend to be more elliptical, have a moderately developed posterior ridge and accompanying sulcus, and have a regularly curved ventral margin. The ventral margin in species such as Epioblasma florentina (Lea 1857) and Epioblasma turqidula (Lea 1858) often exhibit an emargination of the ventrum just anterior to the terminus of the posterior ridge. Yellowish specimens of E. capsaeformis have been mistaken for Epioblasma walkeri (Wilson and Clark 1914) (including records in Johnson [1978: as E. florentina]). Males of E. walkeri tend to be broader and have a rounded posterior ridge; females lack the distinctive darkening of the marsupial expansion.
Reproduction Comments: This species appears to be a long-term brooder. Glochidia have been found in the marsupia during October, May, June and July (Gordon and Layzer, 1989). Spawning probably occurs during late summer and glochidia are released during the late spring and early summer of the following year. During glochidia release, females have been observed to lie upon the surface of the substrate. Seven species of perciform fish have been identified as glochidial hosts for Epioblasma capsaeformis: Etheostoma vulneratum (wounded darter), Etheostoma maculatum (spotted darter), Etheostoma rufilineatum (redline darter), Percina sciera (dusky darter), Cottus baileyi (black sculpin), and Cottus carolinae (banded sculpin) (Yeager and Saylor, 1995; USFWS, 2003; 2004). Juvenile mussels excysted from host fish following 19 - 34 days of parasitism (Yeager, summarized in Hill, 1986). The population fo this species from the Big South Fork Cumberland River transformed in greatest numbers on the greenside darter Etheostoma blennioides, producing an average of 44% of juveniles; less so on the fantail darter, Etheostoma flabellare (24%), and redline darter, Etheostoma rufilineatum (32%). The population from the Duck River (recently proposed as a different species- see Jones et al., 2006) transformed in greatest numbers on the fantail darter Etheostoma flabellare, producing an average of 59% of juveniles and infrequently on the greenside darter, Etheostoma blennioides (17%) and redline darter, Etheostoma rufilineatum (17%) (Jones, 2004). Mantle pad descriptions (which vary by population) and fish lures are described in Jones (2004) and Jones et al. (2006).
Ecology Comments: This species is associated with riffle areas exhibiting high energy flows, high water quality, and rocky substrates (see GHABCOM). This species formerly was quite common throughout its historical range. Some information on population densities is available, but represents sites where the species has already been adveresely affected: 0 - .67/sq. meter (Duck River: Jenkinson, 1988); 0 -.4/sq. meter (Powell River: Jenkinson and Ahlstedt, 1988a); 0 - 2.0/sq. meter (Clinch River: Jenkinson and Ahlstedt, 1988). Quantitative samples from these studies were not necessarily collected in a random manner but are representative of some sites.
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: This species probably is rather sessile with only limited movement in the substrate. Passive downstream movement may occur when mussels are displaced from the substrate during floods. Major dispersal occurs while glochidia are encysted on their hosts.
Riverine Habitat(s): BIG RIVER, CREEK, MEDIUM RIVER, Moderate gradient, Riffle
Special Habitat Factors: Benthic
Habitat Comments: Inhabits moderate to swift currents in large creeks and rivers in substrates composed of coarse sand and gravel to boulder-sized particles, rarely mud. It may be associated with beds of Justicia americana (water willow) bordering the main channel of the riffle (Ortmann, 1924; Gordon and Layzer, 1989). Inhabits small to medium-sized rivers, and sometimes large rivers, in areas with coarse sand to boulder substrate (rarely in mud) and moderate to swift currents. It is sometimes associated with water-willow beds and in pockets of gravel between bedrock ledges in areas of swift current (USFWS, 2003; 2004).
Adult Food Habits: Detritivore
Immature Food Habits: Parasitic
Food Comments: Larvae (glochidia) of freshwater mussels generally are parasitic on fish and display varying degrees of host specificity. No specific trophic studies have been conducted on this species. General literature claims that mussels are filter-feeders that remove phytoplankton from the water column. These assumptions appear to be based on a casual observations of mussels in situ and a few examinations of rectal contents. Baker (1928) speculated that detritus was the primary energy source. This has been substantiated by James (1987) and correlates well with observed microhabitat utilization. This suggests that mussels may occupy a variety of trophic guilds such as postulated for the Sphaeriidae (see Lopez and Holopaien, 1987; Gordon and Layzer, 1989).
Phenology Comments: Little is known concerning the phenology of mussels other than when eggs/glochida are held in the branchial marsupia. Being poikilothermic, activity levels would expectedly be reduced greatly during cold-temperature months.
Length: 7 centimeters
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Listed Endangered throughout its range, except in the free-flowing reach of the Tennessee River from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir and the lower 5 RM of all tributaries to this reach in Colbert and Lauderdale Counties, Alabama (Federal Register, 14 June 2001).

The USFWS, in cooperation with the State of Tennessee and Conservation Fisheries, Inc., proposes to reintroduce this species into its historical habitat in the free-flowing reach of the French Broad River below Douglas Dam to its confluence with the Holston River, Knox County Tennessee, and in the free-flowing reach of the Holston River below Cherokee Dam to its confluence with the French Broad River (Federal Register, 13 June 2006).

Recently, critical habitat was designated for the Duck River (74 river km occupied, 0 river km unoccupied habitat) in Tennessee, Bear Creek (0 river km occupied, 43 river km unoccupied habitat) in Alabama and Mississippi, Powell River (0 river km occupied, 154 river km unoccupied habitat) in Tennessee and Virginia, Clinch River (242 river km occupied, 0 river km unoccupied habitat) in Tennessee and Virginia, Copper Creek (0 river km occupied, 21 river km unoccupied habitat) in Virginia, Nolichucky River (8 river km occupied, 0 river km unoccupied habitat) in Tennessee, Big South Fork (0 river km occupied, 43 river km unoccupied habitat) in Tennessee and Kentucky, and Buck Creek (0 river km occupied, 58 river km unoccupied habitat) in Kentucky (USFWS, 2004).

Recovery plan published (FWS, 2004) with recovery objective: delisting.
Recovery Strategy: The preservation of extant populations and the occupied habitats of these five species is the most immediate and important recovery priority for these mussels. Preservation and protection of these populations will be achieved by continuing to use existing regulatory mechanisms, establishing partnerships with various stakeholders, using best management practices, and minimizing or eliminating threats to the species. Each extant population must also be viable to achieve recovery. Unless a previously unknown population is found, other viable populations within the historic range of each of the five species must be reestablished and protected to effect recovery. Reestablishing new viable populations will require close coordination with and concurrence of the State(s) involved and with other partners that have interests at any potential reintroduction sites. Additional research into the life history and ecological requirements of these mussels as defined in this plan will help formulate the biological information necessary for the preservation of existing or reestablishment and maintenance of other viable populations. Knowledge of the effective population size is particularly critical for determining the size and demographic makeup of a viable population for these species. Due to the rarity of extant populations, propagation of laboratory or hatchery-reared progeny is the most logical means of providing individuals for the establishment of new populations. Facilities that attempt to propagate these mussels should follow the Service's established controlled propagation policy. Priorities for recovery efforts for the five species via propagation should be to develop propagation technology, augment and expand the ranges of extant populations to ensure their viability, and reestablish viable populations in other streams within their historical range that have suitable habitat and water quality. Pursuing and implementing these efforts will enable the recovery of the five species.
Recovery Criteria: Downlisting from endangered to threatened status will occur when the following criteria are met for the protection of extant stream populations, discovery of currently unknown stream populations, and/or reestablishment of historical stream populations: (1) five streams with distinct viable populations of the Cumberland elktoe, six streams with distinct viable populations of the oyster mussel and Cumberlandian combshell, four streams with distinct viable populations of the purple bean, and three streams with distinct viable populations of the rough rabbitsfoot have been established; (2) one distinct naturally reproduced year class exists within each of the viable populations; (3) research studies of the mussels' biological and ecological requirements have been completed and any required recovery measures developed and implemented from these studies are beginning to be successful, as evidenced by an increase in population density of approximately 20 percent and/or an increase in the length of the river reach of approximately 10 percent inhabited by the species as determined through biennial monitoring; (4) no foreseeable threats exist that would likely impact the survival of the species over a significant portion of their ranges; (5) within larger streams the species are distributed over a long enough reach that a single catastrophic event is not likely to eliminate or significantly reduce the entire population in that stream to a status of nonviable; and (6) biennial monitoring of the five species yields the results outlined in criterion (1) above over a 10-year period.
Actions Needed:
1. Utilize existing legislation/regulations to protect current and newly discovered populations.
2. Determine the species' life history requirements and threats and reduce or alleviate those threats which threaten the species.
3. Develop and use an information/education program to solicit the assistance of local landowners, communities, and others to recover the species.
4. Search for additional populations, and through propagation activities, pursue augmentations or reintroductions in order to establish viable populations.
5. Conduct anatomical and molecular genetic analysis of the species to determine the potential occurrence of species complexes or hidden biodiversity.
6. Develop and implement a monitoring program, and annually assess the recovery program where needed.

Biological Research Needs: Determine the preferred habitat and environmental tolerance ranges, sensitivity to various pollutants, and if known glochidial hosts occur at all extant EOs. Possible re-examination of glochidial host may be necessary if the latter is negative and evidence of recent successful reproduction/recruitment is avaiable. Evaluate Big South Fork population to determine if identity is correct or if it is Epioblasma florentina walkeri or an undescribed species.
Population/Occurrence Delineation
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Group Name: Freshwater Mussels

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on some evidence of historical or current presence of single or multiple specimens, including live specimens or recently dead shells (i.e., soft tissue still attached and/or nacre still glossy and iridescent without signs of external weathering or staining), at a given location with potentially recurring existence. Weathered shells constitute a historic occurrence. Evidence is derived from reliable published observation or collection data; unpublished, though documented (i.e. government or agency reports, web sites, etc.) observation or collection data; or museum specimen information.
Mapping Guidance: Based on the separation distances outlined herein, for freshwater mussels in STANDING WATER (or backwater areas of flowing water such as oxbows and sloughs), all standing water bodies with either (1) greater than 2 km linear distance of unsuitable habitat between (i.e. lotic connections), or (2) more than 10 km of apparently unoccupied though suitable habitat (including lentic shoreline, linear distance across water bodies, and lentic water bodies with proper lotic connections), are considered separate element occurrences. Only the largest standing water bodies (with 20 km linear shoreline or greater) may have greater than one element occurrence within each. Multiple collection or observation locations in one lake, for example, would only constitute multiple occurrences in the largest lakes, and only then if there was some likelihood that unsurveyed areas between collections did not contain the element.

For freshwater mussels in FLOWING WATER conditions, occurrences are separated by a distance of more than 2 stream km of unsuitable habitat, or a distance of more than 10 stream km of apparently unoccupied though suitable habitat. Standing water between occurrences is considered suitable habitat when calculating separation distance for flowing water mussel species unless dispersal barriers (see Separation Barriers) are in place.

Several mussel species in North America occur in both standing and flowing water (see Specs Notes). Calculation of separation distance and determination of separation barriers for these taxa should take into account the environment in which the element was collected. Juvenile mussels do not follow this pattern and juveniles are typically missed by most standard sampling methods (Hastie and Cosgrove, 2002; Neves and Widlak, 1987), therefore juvenile movement is not considered when calculating separation distance.

Separation Barriers: Separation barriers within standing water bodies are based solely on separation distance (see Separation Distance-suitable, below). Separation barriers between standing water bodies and within flowing water systems include lack of lotic connections, natural barriers such as upland habitat, absence of appropriate species specific fish hosts, water depth greater than 10 meters (Cvancara, 1972; Moyle and Bacon, 1969) or anthropogenic barriers to water flow such as dams or other impoundments and high waterfalls.
Separation Distance for Unsuitable Habitat: 2 km
Separation Distance for Suitable Habitat: 10 km
Alternate Separation Procedure: None
Separation Justification: Adult freshwater mussels are largely sedentary spending their entire lives very near to the place where they first successfully settled (Coker et al., 1921; Watters, 1992). Strayer (1999) demonstrated in field trials that mussels in streams occur chiefly in flow refuges, or relatively stable areas that displayed little movement of particles during flood events. Flow refuges conceivably allow relatively immobile mussels to remain in the same general location throughout their entire lives. Movement occurs with the impetus of some stimulus (nearby water disturbance, physical removal from the water such as during collection, exposure conditions during low water, seasonal temperature change or associated diurnal cycles) and during spawning. Movement is confined to either vertical movement burrowing deeper into sediments though rarely completely beneath the surface, or horizontal movement in a distinct path often away from the area of stimulus. Vertical movement is generally seasonal with rapid descent into the sediment in autumn and gradual reappearance at the surface during spring (Amyot and Downing, 1991; 1997). Horizontal movement is generally on the order of a few meters at most and is associated with day length and during times of spawning (Amyot and Downing, 1997). Such locomotion plays little, if any, part in the distribution of freshwater mussels as these limited movements are not dispersal mechanisms. Dispersal patterns are largely speculative but have been attributed to stream size and surface geology (Strayer, 1983; Strayer and Ralley, 1993; van der Schalie, 1938), utilization of flow refuges during flood stages (Strayer, 1999), and patterns of host fish distribution during spawning periods (Haag and Warren, 1998; Watters, 1992). Lee and DeAngelis (1997) modeled the dispersal of freshwater into unoccupied habitats as a traveling wave front with a velocity ranging from 0.87 to 2.47 km/year (depending on mussel life span) with increase in glochidial attachment rate to fish having no effect on wave velocity.

Nearly all mussels require a host or hosts during the parasitic larval portion of their life cycle. Hosts are usually fish, but a few exceptional species utilize amphibians as hosts (Van Snik Gray et al., 2002; Howard, 1915) or may metamorphose without a host (Allen, 1924; Barfield et al., 1998; Lefevre and Curtis, 1911; 1912). Haag and Warren (1998) found that densities of host generalist mussels (using a variety of hosts from many different families) and displaying host specialists (using a small number of hosts usually in the same family but mussel females have behavioral modifications to attract hosts to the gravid female) were independent of the densities of their hosts. Densities of non-displaying host specialist mussels (using a small number of hosts usually in the same family but without host-attracting behavior) were correlated positively with densities of their hosts. Upstream dispersal of host fish for non-displaying host specialist mussels could, theoretically, transport mussel larvae (glochidia) over long distances through unsuitable habitat, but it is unlikely that this occurs very often. D. Strayer (personal communication) suggested a distance of at least 10 km, but a greater distance between occurrences may be necessary to constitute genetic separation of populations. As such, separation distance is based on a set, though arbitrary, distance between two known points of occurrence.

Date: 18Oct2004
Author: Cordeiro, J.
Notes: Contact Jay Cordeiro (jay_cordeiro@natureserve.org) for a complete list of freshwater mussel taxa sorted by flow regime.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 23Dec2011
NatureServe Conservation Status Factors Author: Cordeiro, J.
Management Information Edition Date: 06Oct2005
Management Information Edition Author: Cordeiro, J.
Element Ecology & Life History Edition Date: 23Dec2011
Element Ecology & Life History Author(s): Cordeiro, J.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • Ahlstedt, S.A. and J.M. Tuberville. 1997. Quantitative reassessment of the freshwater mussel fauna in the Clinch and Powell rivers, Tennessee and Virginia. Pages 72-97 in K.S. Cummings, A.C. Buchanan, C.A. Mayer, and T.J. Naimo, eds. Conservation and management of freshwater mussels II: initiatives for the future. Proceedings of a UMRCC symposium, 16-18 October 1995, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois.

  • Anthony, J.L. and J.A. Downing. 2001. Exploitation trajectory of a declining fauna: a century of freshwater mussel fisheries in North America. Canadian Journal of Fisheries and Aquatic Sciences, 58: 2071-2090.

  • Baker, F.C. 1928b. The freshwater Mollusca of Wisconsin: Part II. Pelecypoda. Bulletin of the Wisconsin Geological and Natural History Survey, University of Wisconsin, 70(2): 1-495.

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  • Burch, J.B. 1975a. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Malacological Publications: Hamburg, Michigan. 204 pp.

  • Dennis, S.D. 1987. An unexpected decline in populations of the freshwater mussel, Dysnomia (= Epioblasma) capsaaeformis, in the Clinch river of Virginia and Tennessee. Virginia Journal of Science, 38(4): 281-288.

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  • Isom, B. G. and P. Yokley, Jr. 1973. The mussels of the Flint and Paint Rock River Systems of the southwest slope of the Cumberland Plateau in North Alabama-1965 and 1967. The American Midland Naturalist 89(2):442-446.

  • Isom, B.G., P. Yokley, Jr., and C.H. Gooch. 1973. Mussels of Elk River Basin in Alabama and Tennessee- 1965-1967. American Midland Naturalist 89(2):437-442.

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  • Jenkinson, J.J. 1988. Resurvey of freshwater mussel stocks in Duck River, TN. Report to the Tennessee Valley Authority, Knoxville, Tennessee. 20 pp.

  • Jenkinson, J.J. and S.A. Ahlsedt. 1988a. Quantitative reassessment of the freshwater mussel fauna in the Clinch River, Tennessee and Virginia. Tennessee Valley Authority, Knoxville, Tennessee. 28 pp.

  • Jenkinson, J.J. and S.A. Ahlstedt. 1988b. Quantitative reassessment of the freshwater mussel fauna in the Powell River, TN and VA. Tennessee Valley Authority, Knoxville, Tennessee. 28 pp.

  • Johnson, R.I. 1978. Systematics and zoogeography of Plagiola (= Dysnomia = Epioblasma), an almost extinct genus of freshwater mussels (Bivalvia: Unionidae) from middle North America. Bulletin of the Museum of Comparative Zoology, 148(6): 239-320.

  • Jones, J.W. 2004. A holistic approach to taxonomic evaluation of two closely related endangered freshwater mussel species, the oyster mussel (Epioblasma capsaeformis) and tan riffleshell (Epioblasma florentina walkeri) (Bivalvia: Unionidae). MS Thesis, Virginia Polytechnic Institute and State University, Blacksburg, Virginia. 178 pp.

  • Jones, J.W., M. Cuvier, V. David, J. Struthers, N.A. Johnson, R.J. Neves, S.J. O'Brien, and E.M. Hallerman. 2004. Development and characterization of microsatellite loci in the endangered oyster mussel Epioblasma capsaeformis (Bivalvia: Unionidae). Molecular Ecology Notes, 4: 649-652.

  • Jones, J.W., R.J. Neves, M.A. Patterson, C.R. Good, and A. DiVittorio. 2001. A status survey of freshwater mussel populations in the upper Clinch River, Tazewell County, Virginia. Banisteria, 17: 20-30.

  • Jones, J.W., R.J. Neves, S.A. Ahlstedt, and E.M. Hallerman. 2006. A holistic approach to taxonomic evaluation of two closely related endangered freshwater mussel species, the oyster mussel Epioblasma capsaeformis and tan riffleshell Epioblasma florentina walkeri (Bivalvia: Unionidae). Journal of Molluscan Studies, 72: 267-283.

  • Lefevre, G. and W.T. Curtis. 1912. Studies on the reproduction and artificial propogation of fresh-water mussels. Bulletin of the Bureau of Fisheries 30:102-201.

  • Lopez, G.R. and I.J. Holopainen. 1987. Interstitial suspension-feeding by Pisidium spp. (Pisidiiae: Bivalvia): a new guild in lentic benthos? American Malacological Bulletin, 5: 21-29.

  • Mirarchi, R.E., et al. 2004a. Alabama Wildlife. Volume One: A Checklist of Vertebrates and Selected Invertebrates: Aquatic Mollusks, Fishes, Amphibians, Reptiles, Birds, and Mammals. University of Alabama Press: Tuscaloosa, Alabama. 209 pp.

  • Moyle, P. and J. Bacon. 1969. Distribution and abundance of molluscs in a fresh water environment. Journal of the Minnesota Academy of Science 35(2/3):82-85.

  • Ortmann, A.E. 1914. Studies in naiades (in partim). The Nautilus, 28: 28-34.

  • Ortmann, A.E. 1924. The naiad fauna of Duck River in Tennessee. The American Midland Naturalist, 9: 18-62.

  • Parmalee, P.W. and A.E. Bogan. 1998. The freshwater mussels of Tennessee. University of Tennessee Press, Knoxville, Tennesee. 328 pp.

  • Strayer, D. 1983. The effects of surface geology and stream size on freshwater mussel (Bivalvia, Unionidae) distribution in southeastern Michigan, U.S.A. Freshwater Biology 13:253-264.

  • Strayer, D.L. 1999a. Use of flow refuges by unionid mussels in rivers. Journal of the North American Benthological Society 18(4):468-476.

  • Strayer, D.L. and J. Ralley. 1993. Microhabitat use by an assemblage of stream-dwelling unionaceans (Bivalvia) including two rare species of Alasmidonta. Journal of the North American Benthological Society 12(3):247-258.

  • Turgeon, D.D., J.F. Quinn, Jr., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, R.J. Neves, C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F.G. Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.

  • U.S. Fish and Wildlife Service (USFWS). 1997. Determination of Endangered Status for the Cumberland Elktoe, Oyster Mussel, Cumberlandian Combshell, Purple Bean, and Rough Rabbitsfoot. Final rule. Federal Register, 62(7): 1647-1658.

  • U.S. Fish and Wildlife Service (USFWS). 1998. Cumberland elktoe (Alasmidontaq atropurpurea), oyster mussel (Epioblasma capsaeformis), Cumberlandian combshell (Epioblasma brevidens), purple bean (Villosa perpurpurea), and rough rabbitsfoot (Quadrula cylindrica strigillata): Technical Draft Recovery Plan. U.S. Fish and Wildlife Service: Asheville, North Carolina. 119 pp.

  • U.S. Fish and Wildlife Service (USFWS). 2001. Endangered and Threatened Wildlife and Plants; establishment of nonessential experimental population status for 16 freshwater mussels and 1 freshwater snail (Anthony's Riversnail) in the free-flowing reach of the Tennessee River below the Wilson Dam, Colbert and Lauderdale Counties, Alabama. Federal Register, 66(115): 32250-32264.

  • U.S. Fish and Wildlife Service (USFWS). 2003. Endangered and Threatened Widlife and plants; proposed designation of critical habitat for five threatened mussels in the Tennessee and Cumberland River basins; proposed rule. Federal Register, 68(106): 33234-33282

  • U.S. Fish and Wildlife Service (USFWS). 2004. Recovery plan for Cumberland elktoe, oyster mussel, Cumberlandian combshell, purple bean, and rough rabbitsfoot. U.S. Fish and Widlife Service, Atlanta, Georgia. 168 pp.

  • U.S. Fish and Wildlife Service (USFWS). 2006. Endangered and threatened wildlife and plants; establishment of nonessential experimental population status for 15 freshwater mussels, 1 freshwater snail, and 5 fishes in the lower French Broad River and in the lower Holston River, Tennessee; Proposed Rule. Federal Register, 71(113): 34195-34230.

  • Van der Schalie, H. 1938a. The naiad fauna of the Huron River in southeastern Michigan. Miscellaneous Publication of the Museum of Zoology, University of Michigan 40:7-78.

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  • Wells, S.M., R.M. Pyle, and N.M. Collins. 1983. The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland. 632 pp.

  • Williams, J. D., A. E. Bogan, and J. T Garner. 2008. Freshwater mussels of Alabama & the Mobile Basin in Georgia, Mississippi, & Tennessee. University of Alabama Press, Tuscaloosa, Alabama. 908 pages.

  • Williams, J.D., M.L. Warren, Jr., K.S. Cummings, J.L. Harris, and R.J. Neves. 1993b. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9): 6-22.

  • Yeager, B.L. and C.F. Saylor. 1995. Fish hosts for four species of freshwater mussels (Pelecypoda: Unionidae) in the Upper Tennessee River drainage. American Midland Naturalist, 133(1): 1-6.

References for Watershed Distribution Map
  • Barr, W.C., S.A. Ahlstedt, G.D. Hickman, and D.M. Hill. 1993-1994. Cumberlandian mollusk conservation program. Activity 8: Analysis of macrofauna factors. Walkerana 7(17/18):159-224.

  • Biological Resources Division, USGS. 1997. Database of museum records of aquatic species. Compiled by J. Williams (USGS-BRD, Gainesville, FL).

  • Bogan, A.E. 2002. Workbook and key to the freshwater bivalves of North Carolina. North Carolina Museum of Natural Sciences: Raleigh, North Carolina. 101 pp.

  • Hanlon, S.D., M.A. Petty, and R.J. Neves. 2009. Status of native freshwater mussels in Copper Creek, Virginia. Southeastern Naturalist 8(1):1-18.

  • Mirarchi, R.E., J.T. Garner, M.F. Mettee, and P.E. O'Neil. 2004b. Alabama wildlife. Volume 2. Imperiled aquatic mollusks and fishes. University of Alabama Press, Tuscaloosa, Alabama. xii + 255 pp.

  • Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 328 pp.

  • U.S. Fish and Wildlife Service (USFWS). 2004. Endangered and Threatened Widlife and plants; designation of critical habitat for five endangered mussels in the Tennessee and Cumberland River basins; final rule. Federal Register, 69(168): 53135-53180.

  • Williams, J.D., A.E. Bogan, and J.T. Garner. 2008. Freshwater Mussels of Alabama & the Mobile Basin in Georgia, Mississippi & Tennessee. University of Alabama Press: Tuscaloosa, Alabama. 908 pp.

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