(DRAFT) - Taxonomy
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
TAXONOMY
NAME - MUSSEL, PEARLY, BLOSSOM, TURGID-
OTHER COMMON NAMES - MUSSEL, PEARLY, BLOSSOM, TURGID-; BLOSSOM and TURGID-
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 - TURGIDULA,
SCIENTIFIC NAME - EPIOBLASMA TURGIDULA
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Turgid-blossom Pearly Mussel
Epioblasma turgidula (Lea, 1858)
KINGDOM: Animal GROUP: Clam
PHYLUM: Mollusca CLASS: Bivalvia
ORDER: Unionoida FAMILY: Unionidae
E. turgidula is a small Cumberlandian species less than 40 mm
in length with an elliptical, ovate, or obovate outline (01). Valves
are inequilateral and solid with a short hinge ligament. Umbos are
full and elevated in the anterior third of the shell. The
periostracum has irregular growth lines and is a shiny yellow-green
with numerous fine green rays (02). Nacre color is bluish-white.
Sexual dimorphism occurs in this species. The posterior end of
the male is rather pointed and the ventral margin is curved (01). The
male's posterior ridge is doubled and somewhat raised, ending
posteriorly in a slight biangulation (01). In the female, the ventral
margin is straight before the marsupial swelling; the shell is
somewhat concave near the posterior ridges; the posterior marsupial
swelling is similar to or slightly darker than the rest of the shell.
Males are typically elliptical whereas females are obovate in outline
(03). The posterior end of females is thin and irridescent.
Taxonomy - 1 (DRAFT) - Taxonomy
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
This species was initially described from male specimens by Lea
(1858), while the female was described as U. deviatus by Reeve (1864).
These 2 "species" were first recognized as the same species in 1910
(04). Clarification on this species was provided in 1922 (05). E.
turgidula and E. biemarginata may be subspecies of the same species,
but evidence of intermediate forms is lacking (06).
Some controversy still exists among malacologists as to the valid
generic name for this group of species; Epioblasma, Dysnomia, or
Plagiola. All three have been used in the recent literature. A
discussion of these generic names was presented in 1978 (01).
Detailed descriptions and photographs of E. turgidula are
included in previous publications (01,02,03).
Taxonomy - 2 (DRAFT) - Status
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
STATUS
Coded Status
Alabama; Federal Endangered
Alabama; Unofficially Listed
Arkansas; Federal Endangered
Arkansas; State Recognized
Tennessee; Federal Endangered
Tennessee; State Listed
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The turgid-blossom pearly mussel (Epioblasma turgidula) 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, Arkansas, Missouri, and Tennessee.
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 -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),
Status - 1 (DRAFT) - Status
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Alabama
UNOFFICIAL LIST: Extirpated, Bulletin No.2, Endangered and
Threatened Plants and Animals of Alabama,
Alabama Museum of Natural History.
STATE: Arkansas and Missouri
DESIGNATED STATUS: Recognized Endangered
ADMINISTRATIVE AGENCY: (Arkansas) Game and Fish Commission;
(Missouri) Department of Conservation.
STATE STATUTES: (Arkansas) Amendment #35 of Arkansas State
Constitution;
(Missouri) Revised Statutes, 252.240 Wildlife
Code (Regulations) 3C FR 10-4.11.
STATE: Tennessee
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: (Tennessee) Wildlife Resources Agency
STATE STATUTES: (Tennessee) TN Code Ann., Chapter 9, Section
51-901 through 51-912, Proclamation 75-15, 76-4
and amendment.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The turgid-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
76/06/16:41 FR 24367/24368 - 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. turgidula is a riverine species typically found in small to
medium-sized rivers (01). It probably inhabits shoal areas with
rapid current and stable substrate as do other Epioblasma spp. (13).
It is undoubtedly sedentary, intolerant of silt and water pollution,
and requires ample water flow for survival. Eight other species of
Epioblasma, now extinct, were recorded from riffles of large rivers
(13).
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 the life cycle would affect the survival of remnant
populations. 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, TURGID-
Species Id ESIS404014
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, TURGID-
Species Id ESIS404014
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, TURGID-
Species Id ESIS404014
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
(14,15). No study of the food habits of the turgid-blossom has ever
been conducted; required/preferred foods are therefore unknown.
HOME RANGE/TERRITORY:
Non-territorial. The species is sedentary during its adult life
and generally occurred in rivers with others of its kind.
PERIODICITY:
No information exists on this subject for E. turgidula, but other
Epioblasma exhibit a seasonal periodicity (16). During the glochidial
release period in spring, specimens are readily visible in the stream
bottom. After this period, these species burrow in the substrate with
only siphons exposed.
MIGRATION PATTERNS:
Non-migratory.
COVER/SHELTER REQUIREMENTS:
Based on available reports of Epioblasma spp. (01), the species
probably occupies river shoals with swift current and stable
substrate. No species-specific information on cover/shelter is
available in the literature.
REPRODUCTIVE SITE REQUIREMENTS:
The turgid-blossom is a riffle species that occurrs in small to
medium-sized rivers (01). Since this species is apparently sedentary
and movement is inconsequential, this is the type of environment
where all life processes were carried out, including reproduction.
REPRODUCTIVE CHARACTERISTICS:
The reproductive cycle of E. turgidula is similar presumably to
other Epioblasma spp. (03). 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 to
attach to a suitable host for metamorphosis to the free-living
juvenile stage.
The turgid-blossom is probably a long-term breeder (02), 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, TURGID-
Species Id ESIS404014
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.
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 2 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
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 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 Controlling/Restricting Noncommercial Harvest
Beneficial Regulating commercial harvest levels
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 Erosion
Existing Erosion
Adverse
Existing
Management Practices - 1 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
COMMENTS ON MANAGEMENT PRACTICES -
The mussel fauna in most streams of the 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).
Water pollution has probably contributed to the decline of this
species and other Epioblasma spp. Acid mine drainage in tributaries
of the Cumberland River has nearly eliminated the most diverse group
of Epioblasma (10). Numerous tributaries in the upper Tennessee River
drainage were polluted already by the twentieth century and the mussel
fauna was in a decline at that time (11).
The genus Epioblasma has been considered the most highly
developed and recently evolved group of mussel species, with at least
8 of them that have recently become extinct (12). The decline of
E. turgidula and extinction of other Epioblasma cannot be explained,
but appears to be symptomatic of a general synecological problem that
exists between Epioblasma and chronic environmental changes that have
occurred and apparently are continuing in eastern rivers. Because
this species is so rare (possibly extinct), the causes for its decline
will remain conjectural.
Substantial mussel die-offs of unknown origin have
occurred in the Tennessee River drainage since 1982 and have
likely reduced population numbers. Future die-offs pose a direct
threat to species' survival.
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1984. Recovery Plan for
Tuberculed-blossom, Turgid-blossom, and Yellow-blossom Pearly Mussels.
U.S. Fish and Wildlife Service, Atlanta, GA. 39 pp.
Recovery actions for the turgid-blossom pearly mussel include:
(1) Conduct intensive surveys to determine if the species is still
extant.
(2) Once found, identify essential habitat in need of protection.
(3) Utilize existing regulations to protect the species and its
habitat (e.g., controlling take and other factors adversely affecting
the habitat). Habitat restoration or improvement may be necessary for
survival of the species (i.e., restoration of stream banks and
Management Practices - 2 (DRAFT) - Management Practices
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
channels and assuring optimal clean water flow).
(4) Determine present and forseeable threats to the species and
strive to minimize and/or eliminate them. These negative impacts
typically include dredging, strip mining, industrial development, road
and bridge construction, installation and operation of sewage
treatment plants, and the use of herbicides, pesticides and farm
fertilizers.
(5) Utilize artificial culture techniques to produce juvenile mussels
for reintroduction to augment populations.
Except for enforcement of existing regulations, there are
presently no specific recovery actions involving this species.
Management Practices - 3 (DRAFT) - References
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Johnson, R.I. 1978. Systematics and zoogeography of Plagiola
(=Dysnomia=Epioblasma) an almost extinct genus of freshwater
mussels (Bivalvia:Unionidae) from middle North America.
02 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife
volume II: the mollusks. Tenn. Wildlife Resour. Agency, Tenn.
Dep. Conserv., and Tenn. Heritage Prog., Univ. Tenn., Knoxville,
TN. 123 pp.
03 U.S. Fish and Wildlife Service. 1983. Agency Draft Recovery Plan
for the Tubercled-blossom Pearly Mussel [Epioblasma (=Dysnomia)
torulosa torulosa (Rafinesque, 1820)], Turgid-blossom Pearly Mussel
[Epioblasma (=Dysnomia) turgidula (Lea, 1858)], Yellow-blossom
Pearly Mussel [Epioblasma (=Dysnomia) florentina florentina (Lea,
1957)]. U.S. Fish and Wildlife Service, Asheville, NC. 38 pp.
04 Walker, B. 1910. Notes on Truncilla, with a key to the species.
Nautilus 24:75-81.
05 Ortmann, A.E. and B. Walker. 1922. On the nomenclature of certain
North American naiades. Occas. Pap. Mus. Zool. Univ. Mich. No.112.
75 pp.
06 Stansbery, D.H. 1976. Status of endangered fluviatile mollusks
in central North America: Epioblasma turgidula (Lea, 1858). Ohio
State Univ. Res Found. Rep. 12 pp.
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.
10 pp.
09 Salanki, J. 1979. Behavioural studies in mussels under changing
environmental conditions. Symp. Biol. Hung. 19:169-176.
10 Neel, J.K. and W. Allen. 1964. The mussel fauna of the upper
Cumberland Basin before its impoundment. Malacologia 1:427-459.
11 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.
12 U.S. Fish and Wildlife Service. 1984. Recovery Plan for the Tan
Riffle Shell Mussel (Epioblasma walkeri). U.S. Fish and Wildlife
Service, Atlanta, GA. 59 pp.
13 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, Wash., D.C.
14 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.
15 Churchill, E.P., Jr. and S.I. Lewis. 1924. Food and feeding in
freshwater mussels. Bull. U.S. Bur. Fish. 39:439-471.
16 Neves, R.J. 1984. Personal observations. Va. Coop. Fish. Res.
Unit, VPI & SU, Blacksburg, VA.
References - 1 (DRAFT) - References
Species MUSSEL, PEARLY, BLOSSOM, TURGID-
Species Id ESIS404014
Date 13 MAR 96
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 U.S. Fish and Wildlife Service. 1983. Agency Draft Recovery Plan
for the Tubercled-blossom Pearly Mussel [Epioblasma (=Dysnomia)
torulosa torulosa (Rafinesque, 1820)], Turgid-blossom Pearly Mussel
[Epioblasma (=Dysnomia) turgidula (Lea, 1858)], Yellow-blossom
Pearly Mussel [Epioblasma (=Dysnomia) florentina florentina (Lea,
1957)]. U.S. Fish and Wildlife Service, Asheville, NC. 38 pp.
02 Stansbery, D.H. 1976. Naiad mollusks. Pages 45-52. IN:
Endangered and threatened plants and animals of Alabama. Bull.
Ala. Mus. Nat. Hist. No.2.
03 Jenkinson, J.J. 1981. Endangered or threatened aquatic mollusks
of the Tennessee River system. Bull. Am. Malacol. Union
1980:43-45.
04 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.
05 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.
06 Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife
volume II: The mollusks. Tenn. Wildlife Resour. Agency, Tenn.
Dep. Conserv., and Tenn. Heritage Prog., Univ. Tenn., Knoxville,
TN. 123 pp.
07 Simpson, C.T. 1914. A descriptive catalogue of the naiades or
pearly freshwater mussels. Bryant Walker, Detroit, MI. 1540 pp.
References - 2