(DRAFT) - Taxonomy
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
TAXONOMY
NAME - SHELL, RIFFLE, TAN
OTHER COMMON NAMES - SHELL, RIFFLE, TAN; MUSSEL, SHELL, RIFFLE, TAN; MUSSEL, SHELL, RIFFLE-, TAN;MUSSEL, PEARLY, BLOSSOM, BROWN-;MUSSEL, PEARLY, SHELL, RIFFLE- and TAN
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - MOLLUSCA,
CLASS AND SUBCLASS - BIVALVIA,
ORDER AND SUBORDER - UNIONOIDA,
FAMILY AND SUBFAMILY - UNIONIDAE,
GENUS AND SUBGENUS - EPIOBLASMA,
SPECIES AND SSP - WALKERI,
SCIENTIFIC NAME - EPIOBLASMA WALKERI
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Tan Riffle Shell
Epioblasma walkeri (Wilson & Clark, 1914)
KINGDOM: Animal GROUP: Clam
PHYLUM: Mollusca CLASS: Bivalvia
ORDER: Unionoida FAMILY: Unionidae
The tan riffle shell is a medium sized mussel, seldom exceeding
60 mm in length. The shell is elliptical in shape with dull brownish
or yellowish-green periostracum and numerous faint green rays evenly
distributed over the valve surface (01). Nacre color is bluish-white.
This species exhibits sexual dimorphism; the shell of the female has a
pronounced marsupial swelling posteriorly which is thin, has a
multilobed appearance, and is often serrated along the ventral margin
(01,11).
This species is similar to Epioblasma florentina (Lea), the
yellow-blossom pearly mussel, and is sometimes identified as such (07,
11). Common synonyms include: Truncilla walkeri Wilson and Clark,
1914; Dysnomia florentina walkeri (Wilson and Clark, 1914); Dysnomia
florentina f. walkeri; Dysnomia walkeri (Wilson and Clark, 1914) (11);
and Epioblasma florentina form walkeri (Wilson and Clark, 1914) (01).
Complete discussion of taxonomy and synonymy are available (01,03,07,
Taxonomy - 1 (DRAFT) - Taxonomy
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
09,11).
Common names include tan riffle shell mussel (or tan riffle-shell
mussel), the brown-blossom pearly mussel (IUCN Red Data Book, 1983)
and the tan riffle-shell pearly mussel (Tennessee State list).
The literature does not indicate the location of the type
specimen; however, specimens in collections at the Ohio State
University Museum and the University of Tennessee, Knoxville Dept. of
Anthropology Mollusc Collections should be helpful in identification
of the species.
Taxonomy - 2 (DRAFT) - Status
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
STATUS
Coded Status
Alabama; Federal Endangered
Kentucky; Federal Endangered
Kentucky; State Recognized
Tennessee; Federal Endangered
Tennessee; State Listed
Virginia; Federal Endangered
Virginia; State Recognized
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The tan riffle shell (Epioblasma walkeri) has been designated an
Endangered species pursuant to the Endangered Species Act of 1973
(50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as
amended. The species has this status wherever found including the
States of Alabama, Kentucky, Tennessee and Virginia. Critical Habitat
has not been designated.
This species is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild animal
(alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS - Has responsibility for management/recovery, listing,
and law enforcement/protection of this mussel.
NPS - Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public lands under their control. Also responsible
for conservation (Nat. Park System Organic Act - 16
U.S.C. 1, 2-3)/management/recovery on National Park
Service lands. Taking, possessing, or disturbing of
Federally listed species is prohibited on NPS lands
(36 CFR 2.1, 2.2, and 2.3).
Status - 1 (DRAFT) - Status
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Alabama
DESIGNATED STATUS: None.
STATE: Kentucky and Virginia
DESIGNATED STATUS: Recognized Endangered
ADMINISTRATIVE AGENCY: KY Dept. of Fish and Wildlife Resources;
VA Commission of Game and Inland
Fisheries.
STATE STATUTES: KY Rev. Stat. 150-183; KY Admin. Reg. 3:061.
VA Game, Inland Fisheries and Boat Law; Chapter
II, Parag. 29-230 through 29-237.
STATE: Tennessee
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: TN Wildlife Resources Agency
STATE STATUTE: TCA 51-905: Endangered and Threatened Species
List - Creation and Review - Prohibited Acts;
Wildlife Proc. No. 75-15, as amended.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The tan riffle shell is listed in CITES Appendix I and in the
IUCN Red Data Book as Endangered (1983).
ECONOMIC STATUSES:
The species sedentary nature and filter feeding habits may make
it useful as a water quality indicator. It has been shown that
mussels accumulate such pollutants as heavy metals and pesticides.
75/09/26:40 FR 44329/44333 - Proposed rule, list as Endangered
77/08/23:42 FR 42351/42353 - Final rule, listed as Endangered
82/09/27:47 FR 42387/42388 - Five year review
87/07/07:52 FR 25523/25528 - Notice of Review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Cropland and Pasture
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial UB2
Riverine, upper perennial UB1
Riverine, upper perennial RS2
Riverine, upper perennial BB1
COMMENTS ON HABITAT ASSOCIATIONS -
Specific habitat requirements for the tan riffle shell are
unknown. However, collection records provide an indication of the
preferred habitat of the species. The type locality was described as
shallow and turbid with numerous riffles; substrate consisted of loose
rocks and gravel bars with an abundance of water willow (13). In the
Duck River it was found in areas with swift current and gravel-sand
substrate, among dense patches of water weeds (species not named)
(09). It was collected in the Middle Fork Holston River in riffle
habitat below a rock outcropping (05).
The tan riffle shell appears to occur in riffle or shoal areas of
small to moderate-sized rivers with swift regular current and stable
substrate of gravel and sand.
Pastureland is the primary land type bordering tan riffle shell
habitat.
Habitat Associations - 1 (DRAFT) - Food Habits
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General Detritus
General Phytoplankton
General Diatoms
General Algae
General Zooplankton
General Fish
Food Habits - 1 (DRAFT) - Environment Associations
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Aquatic Features: Pool areas
Environment Associations - 1 (DRAFT) - Life History
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
The food habits of the tan riffle shell are unknown. However, it
probably exhibits food habits similar to other mussel species. Adult
tan riffle shells, like other freshwater mussels, are filter feeders
(18,20). Freshwater mussels feed on detritus, diatoms, phytoplankton,
and zooplankton (16). Water is drawn into the mussel through the
inhalant siphon and passed over specialized gills which filter out
suspended food particles (20). It is not known, however, which
particles are used as nutritional sources, or if some are passed
through the gut intact (21).
Mature glochidia, or larvae, are released by the female during
the spring and summer (15). These glochidia attach to the fins or
gills of certain host fish to encyst and metamorphose to the juvenile
stage (15). During this period the glochidia are sustained by the
tissues of their host (20).
HOME RANGE/TERRITORY:
There is no information available. The tan riffle shell is a
sedentary species, as are all mussel species, and barring
environmental changes such as drying of the river, it probably
remains in one place throughout its adult life.
PERIODICITY:
There is no information available.
MIGRATION PATTERNS:
There is no literature documenting migration in mussels.
COVER/SHELTER REQUIREMENTS:
The cover and shelter requirements of the tan riffle shell are
largely unknown. The type locality was described as shallow and
turbid with numerous riffles; substrate consisted of loose rocks and
gravel bars with an abundance of water willow (13). In the Duck River
it was found in areas with swift current and gravel-sand substrate,
among dense patches of water weeds (species not named) (09). It was
collected in the Middle Fork Holston River in riffle habitat below a
rock outcropping (05).
The tan riffle shell appears to occur in riffle or shoal areas of
small to moderate-sized rivers with swift regular current and stable
substrate of gravel and sand.
REPRODUCTIVE SITE REQUIREMENTS:
There is no information available for the tan riffle shell.
Since it is sedentary, reproduction probably takes place in the
riffles where it occurs.
REPRODUCTIVE CHARACTERISTICS:
Based on information available for other lampsiline species, the
tan riffle shell is probably a long term breeder (bradytictic) (01,06,
08,14,17). Females take in sperm through the incurrent siphon during
mid and late summer. Mature glochidia remain in the marsupia in the
Life History - 1 (DRAFT) - Life History
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
gills of the female from early fall through winter, and are released
into the water column the following spring. Depending on the size of
the mussel, a female may release several hundred thousand glochidia
(18). Lampsiline mussels reach sexual maturity as early as age three.
PARENTAL CARE:
There is no literature available that documents parental care in
the tan riffle shell.
POPULATION BIOLOGY:
The population biology of the tan riffle shell is unknown.
SPECIES INTERRELATIONSHIPS:
The glochidia of the tan riffle shell are probably obligate
parasites on the gills of certain fish. Mussel glochidia must attach
to the gills or fins of appropriate fish hosts to complete their life
cycles, and fish host specificity has been documented (14,17,18).
However, the fish host(s) required by the tan riffle shell are
unknown.
Life History - 2 (DRAFT) - Management Practices
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Maintaining/Controlling Water Flow
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Controlling/Restricting Pesticide Use
Beneficial Controlling/Restricting Agricultural Practice
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting wild animals
Beneficial Transplanting Wild Eggs/Wild Seeds
Beneficial Restricting Poaching
Beneficial Controlling/Restricting Noncommercial Harvest
Adverse Surface Mines
Existing Surface Mines
Adverse Rural Residential/Industrial Areas
Existing Rural Residential/Industrial Areas
Adverse Water Temperature Alteration
Existing Water Temperature Alteration
Adverse Water Level Fluctuation
Existing Water Level Fluctuation
Adverse Reservoirs
Existing Reservoirs
Adverse Siltation
Existing Siltation
Adverse Dredging
Existing Dredging
Adverse Applying fertilizers
Existing Applying fertilizers
Adverse Applying pesticides
Existing Applying pesticides
Adverse Environmental Contamination/Pollution
Existing Environmental Contamination/Pollution
COMMENTS ON MANAGEMENT PRACTICES -
Destruction and alteration of habitat, and water quality
degradation in the Tennessee and Cumberland River drainages are
responsible for the decline and present status of the tan riffle
shell.
Dam construction appears to have had major impacts on populations
of the tan riffle shell throughout its range. Cold water discharges
have been, and continue to be, detrimental to mussel populations below
dams (14). Dams on the Middle and South Forks of the Holston River
have impounded those rivers in Sullivan Co., TN and Washington Co.,
VA, and eliminated habitat within its historic range (15). Closure of
Wolf Creek Dam impounded the Cumberland River and the lower reaches of
its major tributaries, including habitat of the tan riffle shell in
Beaver Creek (04). The population in the Stones River system has been
partially or entirely eliminated by the J. Percy Priest Reservoir (10,
Management Practices - 1 (DRAFT) - Management Practices
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
11).
Other factors contributing to the decline of the tan riffle shell
include siltation and pollution. Silt from gravel dredging operations
coupled with summer low flow conditions is thought to have contributed
to decline of naiads in the Stones River system (10). Inputs of
mercury, acid mine drainage, organic wastes, and fertilizers and
pesticides have resulted in the decline of the tan riffle shell and
other naiad species (02,04,10,15).
Pollution is the major factor threatening the remaining
population of the tan riffle shell in the Middle Fork Holston River
(15). The Holston River drainage is susceptible to pollution (12) due
to natural background levels of manganese. Domestic pollution may
thus constitute a major threat to the continued survival of the tan
riffle shell in the Middle Fork (11,15).
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1984. Tan Riffle Shell Mussel
Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, GA. 59 pp.
Management actions recommended for the recovery of the tan riffle
shell include:
1. Research to determine the species current distribution and range,
habitat requirements, life history, and population biology.
2. Monitor the known populations and document apparent threats to
the species such as siltation (from poor agricultural practices,
road and bridge construction, and urban development),
channelization, flood control, pesticide use, municipal sewage
effluents, and other environmental contaminants. Eliminate these
threats.
3. Investigate the feasibility of establishing special sanctuaries,
state refuges, cooperative agreements or easements with land
owners, and land use zoning or other means to protect tan riffle
shell habitat from adverse development and non-commercial
collecting (poaching).
4. Determine the feasibility of introducing the species into 3
additional rivers and establishing new population centers in the
Middle Fork Holston River; implement where feasible. Develop
successful methods of reintroduction such as transplanting wild
adults, glochidia infested hosts, juveniles; or through
artificially cultured individuals or other means.
5. Educate the public, particularly landowners along the rivers
where it occurs, to define and encourage their roles in
protection of endangered species and to gain support for habitat
protection.
Management Practices - 2 (DRAFT) - References
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
References
*****REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE*****
01 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife,
Volume II: The mollusks. Tenn. Wildl. Resour. Agency, Tenn. Dept.
Conserv. and Tenn. Heritage Prog. Univ Tenn., Knoxville. 123 pp.
02 Carter, L.J. 1977. Chemical plants leave unexpected legacy in two
Virginia rivers. Science 198:1015-1020.
03 Johnson, R.I. 1978. Systematics and zoogeography of Plagiola
(=Dysnomia=Epioblasma) an almost extinct genus of freshwater
mussels (Bivalvia:Unionidae) from middle North America. Bull. Mus.
Comp. Zool. 148:239-321.
04 Neel, J.K. and W.R. Allen. 1964. The mussel fauna of the upper
Cumberland Basin before its impoundment. Malacologia 1:427-459.
05 Neves, R.J., G.B. Pardue, E.F. Benfield, and S.D. Dennis. 1980.
An evaluation of endangered mollusks in Virginia. Final report on
Proj. No. E-F-1, on file at: Va. Comm. Game Inland Fish.,
Richmond. 140 pp.
06 Ortmann, A.E. 1911. Monograph of the naiades of Pennsylvania.
Mem. Carnegie Mus. 4:279-347.
07 Ortmann, A.E. 1918. The nayades (freshwater mussels) of the upper
Tennessee drainage with notes on synonymy and distribution. Proc.
Am. Phil. Soc. Phila. 57:521-626.
08 Ortmann, A.E. 1919. A monograph of the naiades of Pennsylvania:
Part III, Systematic account of the genera and species. Mem.
Carnegie Mus. 8:1-389.
09 Ortmann, A.E. 1924. The naiad fauna of Duck River in Tennessee.
Am. Midl. Nat. 9:18-62.
10 Schmidt, J.E. 1982. The freshwater mussels of the Stones River
above J. Percy Priest Reservoir, Tennessee. M.S. Thesis, Tenn.
Tech Univ., Cookeville. 65 pp.
11 Stansbery, D.H. 1976. Status of endangered fluviatile mollusks in
central North America: Epioblasma walkeri (Wilson & Clark 1914).
Ohio St. Univ. Res. Found. Rep. On file at: Dept. Interior, Fish
Wildl. Serv., Office of Endangered Species, Washington, D.C. 7 pp.
12 Young, G.J. and R.D. Blevins. 1981. Heavy metal concentrations in
the Holston River Basin (Tennessee). Arch. Environ. Contam.
Toxicol. 10:541-560.
13 Wilson, C.B. and H.W. Clark. 1914. The mussels of the Cumberland
River and its tributaries. Bur. Fish. Doc. No. 781. 63 pp.
14 Zale, A.V. and R.J. Neves. 1982. Reproductive biology of four
freshwater mussel species (Mollusca:Unionidae) in Virginia.
Freshwat. Invert. Biol. 1:17-28.
15 U.S. Fish and Wildlife Service. 1984. Tan Riffle Shell Mussel,
Epioblasma (=Dysnomia) walkeri, Recovery Plan. U.S. Fish and
Wildlife Service, Atlanta, GA. 59 pp.
16 Churchill, E.P., Jr. and S.I. Lewis. 1924. Food and feeding in
freshwater mussels. Bull. U.S. Bur. Fish. 39:439-471.
17 Coker, R.E., A.F. Shira, H.W. Clark, and A.D. Howard. 1921.
Natural history and propagation of fresh-water mussels. Bull. U.S.
Bur. Fish. 37:77-181.
18 Surber, T. 1912. Notes on the natural hosts of freshwater
References - 1 (DRAFT) - References
Species SHELL, RIFFLE, TAN
Species Id ESIS404002
Date 13 MAR 96
mussels. Bull. U.S. Bur. Fish. 32:110-116.
19 Parker, W. and L. Dixon. 1980. Endangered and threatened wildlife
of Kentucky, North Carolina, South Carolina and Tennessee. U.S.
Fish and Wildlife and N.C. Agric. Ext. Serv., AG-185. 115 pp.
20 White, C.P. 1982. Endangered and threatened wildlife of the
Chesapeake Bay region: Delaware, Maryland and Virginia. Tidewater
Publishers, Centerville, MD 147 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife.
Vol. II: The mollusks. Tenn. Wildl. Resour. Agency. Tenn. Dept.
Conserv. and Tenn. Heritage Prog., Univ. TN, Knoxville. 123 pp.
02 Johnson, R.I. 1978. Systematics and zoogeography of Plagiola
(=Dysnomia=Epioblasma) an almost extinct genus of freshwater
mussels (Bivalvia:Unionidae) from middle North America. Bull. Mus.
Comp. Zool. 148:239-321.
03 Neel, J.K. and W.R. Allen. 1964. The mussel fauna of the upper
Cumberland Basin before its impoundment. Malacologia 1:427-459.
04 Neves, R.J., G.B. Pardue, E.F. Benfield, and S.D. Dennis. 1980.
An evaluation of endangered mollusks in Virginia. Unpublished
report on file at: Va. Comm. Game Inland Fish., Proj. No. E-F-1.
Richmond, VA. 140 pp.
05 Neves, R.J. May 1983. Personal communication. 106 Cheatham Hall,
VPI&SU, Blacksburg, VA 24061.
06 Ortmann, A.E. 1918. The nayades (freshwater mussels) of the upper
Tennessee drainage with notes on synonymy and distribution. Proc.
Am. Phil. Soc., Phila. 57:521-626.
07 Ortmann, A.E. 1924. The naiad fauna of Duck River in Tennessee.
Am. Midl. Nat. 9:18-62.
08 Ortmann, A.E. 1925. The naiad-fauna of the Tennessee River system
below Walden Gorge. Am. Midl. Nat. 9:321-372.
09 Stansbery, D.H. 1976. Status of endangered fluviatile mollusks in
central North America: Epioblasma walkeri (Wilson & Clark 1914).
Ohio St. Univ. Res. Found. Rep., U.S. Dept. Interior, Fish Wildl.
Serv., Bur. Sport Fish. Wildl. 7 pp.
10 Stansbery, D.H. and W.J. Clench. 1975. The Pleuroceridae and
Unionidae of the Middle Fork Holston River in Virginia. Bull. Am.
Malacol. Union 1974:51-54.
11 Stansbery, D.H. and W.J. Clench. 1978. The Pleuroceridae and
Unionidae of the upper South Fork Holston River in Virginia. Bull.
Am. Malacol. Union 1977:75-78.
12 van der Schalie, H. 1973. The mollusks of the Duck River drainage
in central Tennessee. Sterkiana 52:45-56.
13 Wilson, C.B. and H.W. Clark. 1914. The mussels of the Cumberland
River and its tributaries. Bur. Fish. Doc. No. 781. 63 pp.
14 Widlak, James C. 1987. Personal knowledge. Endangered Species
Field Office, USFWS, 100 Otis St., Room 224, Asheville, NC 28801.
References - 2