(DRAFT) - Taxonomy
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
TAXONOMY
NAME - MUSSEL, PEARLY, BLOSSOM, GREEN-
OTHER COMMON NAMES - MUSSEL, PEARLY, BLOSSOM, GREEN-;BLOSSOM and GREEN-
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 - TORULOSA, GUBERNACULUM
SCIENTIFIC NAME - EPIOBLASMA TORULOSA GUBERNACULUM
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Green-blossom Pearly Mussel
Epioblasma torulosa gubernaculum (Reeve, 1865)
KINGDOM: Animal GROUP: Clam
PHYLUM: Mollusca CLASS: Bivalvia
ORDER: Unionoida FAMILY: Unionidae
E. t. gubernaculum is a compressed headwaters form of E.
torulosa. It is a medium-sized Cumberlandian species with a shell
outline described as irregularly ovate, elliptical, or obovate (01,
02). Valves are inequilateral and solid with a short hinge ligament;
umbos are full, somewhat turned forward, and in the anterior third of
the shell (02). The periostracum has many distinct growth lines and
is smooth and shiny, straw to yellow-green in color with numerous fine
green rays. Poorly developed knobs may be present across the medial
and/or posterior ridges.
Sexual dimorphism occurs in this species. The posterior ridge in
males is low and separated from the medial ridge by a furrow which
ends ventrally in an emargination between the ridges (02). Females
are typically larger than males and possess broadly rounded marsupial
swellings extending from the mid-ventral margin to the posterior end.
These swellings are somewhat flattened and dark green, occasionally
Taxonomy - 1 (DRAFT) - Taxonomy
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
marked by small radial furrows (02).
Beak cavity of this species is shallow, and the pallial line and
muscle scars are prominent. Nacre color ranges from white to salmon
(03,04). Detailed descriptions and photographs of E. t. gubernaculum
are included in previous publications (01,02,04,05).
The form gubernaculum apparently graded into the big river form,
torulosa, in the Tennessee River near Knoxville. In the Ohio River
system, the form rangiana occurs (02). Clinal variation of the E.
torulosa subspecies has been described (06). Some controversy still
exists as to the valid generic name for these species, Epioblasma,
Dysnomia, or Plagiola. All three have been used in the recent
literature. A discussion of these generic names was presented in 1978
(04).
Taxonomy - 2 (DRAFT) - Status
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
STATUS
Coded Status
Tennessee; Federal Endangered
Tennessee; State Listed
Virginia; Federal Endangered
Virginia; State Recognized
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The green-blossom pearly mussel (Epioblasma torulosa
gubernaculum) 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 subspecies has this
status wherever found including the States of Tennessee and Virginia.
This subspecies 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 -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD (COE) -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
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:
Status - 1 (DRAFT) - Status
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
STATE: Tennessee
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Wildlife Resources Agency
STATE STATUTES: TN Code Ann., Chapter 9, Sec. 51-901 through
51-912, and Proclamations 75-15, 76-4 and
amendments.
STATE: Virginia
DESIGNATED STATUS: Recognized Endangered
ADMINISTRATIVE AGENCY: Commission of Game and Inland Fisheries
STATE STATUTES: State Code 29.231 to 29.237.
INTERNATIONAL STATUSES, TREATIES AND AGREEMENTS:
The green-blossom pearly mussel is listed in appendix I of CITES
and is listed as Endangered in the IUCN Red Data Book, 1983.
ECONOMIC STATUSES:
There are no known commercial values, however 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.
74/10/17:39 FR 37078/37079 - Notice of review
75/09/26:40 FR 44329/44333 - Proposed rule
76/06/14:41 FR 24062/24067 - Final rule, listed as Endangered
76/06/16:41 FR 24367/24378 - Proposal - CITES I
77/02/22:42 FR 10484/10485 - Final - CITES I
81/02/27:46 FR 14652/14658 - Five year review
87/07/07:52 FR 25523/25528 - Notice of review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
INLAND AQUATIC
LAND USE -
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial UB1
Riverine, upper perennial SB1
COMMENTS ON HABITAT ASSOCIATIONS -
E. t. gubernaculum is a Cumberlandian species inhabiting riffle
and shoal areas in medium-sized (3-6 order) streams. Habitat is
typically sand and gravel substrates with moderate to fast current
(01). This species does not occur in the impounded sections of
rivers. It is apparently quite sedentary, appears to be intolerant of
silt and pollution, and requires ample water flow and stable substrate
for survival. Eight species of Epioblasma, now presumed extinct,
were recorded from riffles of large rivers (15).
Habitat of the glochidia is initially within the gills of the
female, then in the water column, and finally attached to a suitable
fish host. Any alteration of these life stage-specific habitats
during its life cycle would likely affect the long-term success of the
remaining population. Habitat requirements or associations for the
juvenile stage are unknown. Specific environmental requirements for
the adults are also unknown.
Habitat Associations - 1 (DRAFT) - Food Habits
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General Detritus
General Bacteria
General Phytoplankton
General Diatoms
General Zooplankton
General Fish
Food Habits - 1 (DRAFT) - Environment Associations
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
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 MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
LIFE HISTORY
FOOD HABITS:
There are no known interspecific differences in feeding among
freshwater mussels (07). The glochidia are probably obligate
parasites on the gills or fins of fish. Adult mussels are
filter-feeders and consume particulate matter suspended in the water
column. Identifiable stomach contents almost invariably include mud,
desmids, diatoms, other unicellular algae, protozoa, and zooplankters
(16,17). No study of the food habits of the green-blossom has been
conducted; required/preferred foods are therefore unknown.
HOME RANGE/TERRITORY:
Non-territorial. The species is sedentary during its adult life
and generally occurs in streams with others of its kind.
PERIODICITY:
Nothing is known about this species, but other Epioblasma exhibit
a seasonal periodicity (18). During the spawning period in spring,
specimens are readily visible in the stream bottom. After spawning,
these species burrow in the substrate with only siphons exposed.
MIGRATION PATTERNS:
Non-migratory.
COVER/SHELTER REQUIREMENTS:
The species occurs primarily in shallow water with moderate to
fast current and stable, mixed substrate. No species-specific
information on cover/shelter is available in the literature.
REPRODUCTIVE SITE REQUIREMENTS:
The green-blossom is a riffle and run species that occurred in
free-flowing, medium-sized streams with moderate flow (01). Habitat
is typically shallow water shoal areas with stable, mixed substrate.
Since this species appears to be sedentary and movement is
inconsequential, this is the type of environment where all life
processes are carried out, including reproduction.
REPRODUCTIVE CHARACTERISTICS:
The reproductive cycle of E. t. gubernaculum is presumed to be
similar to other Epioblasma spp. (01). During spawning, males
discharge sperm into the water column, and the sperm are taken in by
the females during siphoning. Eggs are fertilized in the female's
suprabranchial cavity or gills, which serve as marsupia for embryos
developing to the parasitic stage (glochidia). Glochidia are released
by the female and must attach to a suitable host for metamorphosis to
the free-living juvenile stage.
The green-blossom is probably a long-term breeder (19), spawning
in late summer, retaining glochidia through fall and winter, and
releasing glochidia the following spring/summer. The fish host(s) are
unknown.
PARENTAL CARE:
Life History - 1 (DRAFT) - Life History
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
Except for retention of the glochidia within the gills of the
female prior to release, no parental care occurs.
POPULATION BIOLOGY:
No information exists on the population biology of this species.
SPECIES INTERRELATIONSHIPS:
The required fish hosts for the parasitic glochidia of this
species are unknown (01).
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 2 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Developing/maintaining stream structures
Beneficial Maintaining/Controlling Water Flow
Beneficial Controlling/Restricting Mining
Beneficial Controlling/Restricting Road Maintainance Actions
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Land Acquisition
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Controlling/Restricting Pesticide Use
Beneficial Controlling/Restricting Herbicide 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 Collecting
Existing Collecting
Adverse Inherent Reproductive Characteristics
Existing Inherent Reproductive Characteristics
Adverse Low Gene Pool
Existing Low Gene Pool
Adverse Underground Mines
Existing Underground Mines
Adverse Surface Mines
Existing Surface Mines
Adverse Siltation
Existing Siltation
Adverse Water Temperature Alteration
Existing Water Temperature Alteration
Adverse Dissolved Oxygen Reduction
Existing Dissolved Oxygen Reduction
Adverse Water Level Fluctuation
Existing Water Level Fluctuation
Adverse Reservoirs
Existing Reservoirs
Adverse Migration barriers
Existing Migration barriers
Adverse Dredging
Existing Dredging
Adverse Applying herbicides
Existing Applying herbicides
Adverse Applying pesticides
Existing Applying pesticides
Adverse Environmental Contamination/Pollution
Existing Environmental Contamination/Pollution
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Erosion
Existing Erosion
Management Practices - 1 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
RESULT MANAGEMENT PRACTICE
Adverse
Existing
COMMENTS ON MANAGEMENT PRACTICES -
The mussel fauna in most streams of the upper Tennessee River
drainage has been impacted by dam construction, channelization,
siltation and water pollution, which directly affect all mussel
species (01,07). The change from lotic to lentic conditions because
of dams has also altered the species composition of the fish
community, thus jeopardizing the reproductive success of some mussel
species by eliminating required fish hosts. Although siltation has
been suggested as the most significant adverse effect of impoundments
on mussels (07), other detrimental factors include lowered water
temperatures, pH changes, oxygen depletion, and dewatering of mussel
beds below dams (07). Mussel deaths can occur in substrate on which
0.6-2.5 cm of silt has accumulated, resulting in interference with
feeding and suffocation (08). The siphoning period and metabolic rate
of mussels can also be affected by such contaminants as heavy metals
and agricultural chemicals (09).
Coal waste from mining activities in southwestern Virginia has
probably contributed to the decline of this species. Coal processing
plants in the Clinch River and Powell River have contributed
particulate matter to the rivers and altered substrate composition
(01,10).
Water pollution is another major factor that has apparently
contributed to the decline of this species and other Epioblasma spp.
Acid mine drainage in headwater tributaries of the Cumberland River
has nearly eliminated the most diverse group of Epioblasma (11).
Numerous streams in the upper Tennessee drainage were polluted already
by early twentieth century, and the mussel fauna was in a decline at
that time (12). The historic population in the Clinch River was
likely affected by chemical spills in 1967 and 1970 at the APCO plant
in Carbo, VA (13,14).
All of the factors mentioned above (impoundments, siltation, coal
mining, and water pollution) are still considered potential threats to
the remaining population of E. t. gubernaculum. Other factors that
may also be affecting this species include collecting by
conchologists, invasion of the Asiatic clam (Corbicula fluminea), and
the small gene pool which may be below minimum population size needed
for sufficient genetic variation to respond to environmental changes.
Substantial mussel die-offs of unknown origin that have
occurred in the Tennessee River drainage since 1982 also pose a
direct threat to the species' survival.
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1984. Green-blossom Pearly Mussel
Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, GA. 50 pp.
Recovery actions for the green-blossom pearly mussel include:
Management Practices - 2 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
(1) Continue to utilize existing legislation and regulations to
protect the species and its habitat. Immediate protection of the only
known population, located in the Clinch River, is crucial to the
continued survival of the spp. and to gain the knowledge needed to
save it from extinction.
(2) Conduct population and habitat surveys to determine the status
and range of the species.
(3) Determine present and forseeable threats to the species and
strive to minimize and/or eliminate them. These negative impacts are
likely to include coal related pollution, road construction, dredging,
herbicide and pesticide spraying, industrial development, and
chlorinated effluents.
(4) Identify essential habitat in need of protection. Investigate
the use of Scenic River status, mussel sanctuaries, land acquisition,
and/or other means for the protection of this habitat and utilize
where feasible.
(5) Determine the feasibility of introducing the species back into
its historic range and introduce where feasible. Determine the best
methods for establishing new populations (e.g., introduction of adult
mussels, juveniles, infected fish hosts, artificially cultured
individuals and/or other means). Habitat restoration or improvement
may by necessary to improve conditions for survival of the species
(i.e., restoration of stream banks and channels and assurring optimum
clean water flow). It is unlikely that removal from the Federal
endangered or threatened species list could be achieved without the
establishment of populations in other rivers and the expansion of the
Clinch River population.
Present recovery efforts involve studies to determine the impact
of chlorine, enforcement of regulations, and information/education
efforts.
Management Practices - 3 (DRAFT) - References
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 U.S. Fish and Wildlife Service. 1983. Recovery Plan for the
Green-blossom Pearly Mussel [Epioblasma (=Dysnomia) torulosa
gubernaculum (Reeve, 1865)]. U.S. Fish and Wildlife Service,
Atlanta, GA. 50 pp.
02 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife
volume II: the mollusks. Tenn. Wildl. Resour. Agency, Tenn.
Dep. Conserv., and Tenn. Heritage Prog., Univ. Tenn., Knoxville,
TN. 123 pp.
03 Simpson, C.T. 1914. A Descriptive Catalogue of the Naiades or
Pearly freshwater Mussels. Bryant Walker, Detroit, MI. 3 volumes,
1540 pp.
04 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. 148:239-320.
05 Parker, W. and L. Dixon. 1980. Endangered and Threatened wildlife
of Kentucky, North Carolina, South Carolina, and Tennessee. NC.
Agric. Ext. Serv. 122 pp.
06 Ball, G.H. 1922. Variation in freshwater mussels. Ecology
3:93-121.
07 Fuller, S.L.H. 1974. Clams and mussels (Mollusca:Bivalvia).
Pages 215-273. IN: C.W. Hart and S.L.H. Fuller (eds.), Pollution
Ecology of Freshwater Invertebrates. Academic Press, NY.
08 Ellis, M.M. 1931. Some factors affecting the replacement of the
commercial fresh-water mussels. U.S. Bur. Fish. Circ. No.7. 10pp.
09 Salanki, J. 1979. Behavioural studies in mussels under changing
environmental conditions. Symp. Biol. Hung. 19:169-176.
10 Neves, R.J., G.B. Pardue, E.F. Benfield, and S.D. Dennis. 1980.
An evaluation of endangered mollusks in Virginia. Final Rep. VA.
Comm. Game Inland Fish. Proj. No.E-F-1. 140 pp.
11 Neel, J.K. and W. Allen. 1964. The mussel fauna of the upper
Cumberland Basin before its impoundment. Malacologia 1:427-459.
12 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.
13 Raleigh, R.F., D.H. Bennett, and L.O. Mohn. 1978. Changes in fish
stocks after major fish kills in the Clinch River near St. Paul,
Virginia. Am. Midl. Nat. 99:1-9.
14 Cairns, J., Jr., J.S. Crossman, K.L. Dickson, and E.E. Herricks.
1971. The recovery of damaged streams. Assoc. Southeast. Biol.
Bull. 18:79-106.
15 Stansbery, D.H. 1971. Rare and endangered mollusks in eastern
United States. Pages 5-18. IN: S.E. Jorgenson and R.E. Sharp
(eds.). Proceedings of a symposium on rare and Endangered mollusks
(naiades) of the U.S. Bur. Sport. Fish. Wildl., U.S. Fish and
Wildlife Service., Washington, D.C.
16 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.
References - 1 (DRAFT) - References
Species MUSSEL, PEARLY, BLOSSOM, GREEN-
Species Id ESIS404013
Date 13 MAR 96
17 Churchill, E.P., Jr., and S.I. Lewis. 1924. Food and feeding in
freshwater mussels. Bull. U.S. Bur. Fish. 39:439-471.
18 Neves, R.J. 1984. Personal observations. VA. Coop. Fish. Res.
Unit, VPI & SU, Blacksburg, VA.
19 Ortmann, A.E. 1919. Monograph of the naiades of Pennsylvania.
Mem. Carnegie Mus. 4:279-347.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 U.S. Fish and Wildlife Service. 1983. Recovery Plan for the
Green-blossom Pearly Mussel [Epioblasma (=Dysnomia) torulosa
gubernaculum (Reeve, 1865)]. U.S. Fish and Wildlife Service,
Atlanta, GA. 50 pp.
02 Bates, J.M. and S.D. Dennis. 1978. The mussel fauna of the Clinch
River, Tennessee and Virginia. Sterkiana 69-70:3-23.
03 Stansbery, D.H. 1971. Rare and endangered mollusks in eastern
United States. Pages 5-18. IN: S.E. Jorgenson and R.E. Sharp
(eds.), Proc. of a symposium on rare and Endangered mollusks
(naiades) of the U.S. Bur. Sport Fish. Wildl., U.S. Fish and
Wildlife Service.
04 Stansbery, D.H. 1970. Eastern freshwater mollusks. I. The
Missippi and St. Lawrence River systems. Pages 9-22. IN: A.H.
Clarke (ed.), Rare and Endangered mollusks of North America.
Malacologia 13.
05 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.
06 Johnson, R.I. 1978. Systematics and zoogeography of Plagiola
(=Dysonomia=Epioblasma) an almost extinct genus of freshwater
mussels (Bivalvia:Unionidae) from Middle North America. Bull. Mus.
Comp. Zool. 148:239-320.
References - 2