Freshwater Mussels On Georgia's List of Federally Protected Species
Kim D. Coder
Warnell School of Forest Resources
The University of Georgia
On April 16, 1993 eleven species of freshwater mussels were given protection
under the Endangered Species Act. Nine of these mussel species have ranges
that extend into northwest Georgia. Mussels are unsegmented invertebrates
that produce a two piece shell with a pearl-like inner surface. Generically,
many people call them clams or naiads.
The nine species with historic or current populations in Georgia include:
||AL, GA, TN
||AL, GA, TN
||AL, GA, MS
||AL, GA, MS, TN
||AL, GA, MS, TN
Upland Combshell (Epioblasma metastriata)
Bivalve up to 2.4 inches in length. Male and female look distinctly different.
External color is yellow-brown to tan sometimes with broken green lines
or green spots. Could be known as Unio compactus or Unio metastriatus.
Found in the Conasauga River in Georgia.
Southern Acornshell (Epioblasma othcaloogensis)
Bivalve up to 1.2 inches in length. Male and female appear distinctly different.
External color is yellow with a smooth, shiny texture. Could be known as
Unio othcaloogensis or Unio modicellus. Found in the upper
Coosa River system streams.
Fine-lined Pocketbook (Lampsilis altilis)
Bivalve rarely exceeding 4 inches in length. External color is yellow-brown
to black with fine lines on the underside. The inner surface of the shell
is white. Could be known as Unio altilis, Unio clarkianus,
or Unio gerhardtii. Found in the head waters of the Sipsey Fork
(including Rush and Brushy Creeks) and North River of the Black Warrior
River drainage, Tatum Creek in the Alabama River drainage, Little Cahaba
River in the Cahaba River drainage, Conasauga River in the Coosa River
drainage (one site in main channel), and Chewacla and Opintlocco Creeks
in the Tallapoosa drainage. Species appears confined to creek habitats.
Alabama Moccasinshell (Medionidus acutissimus)
Bivalve up to 1.2 inches in length with a thin shell. External color is
yellowish to brownish yellow with broken green lines. The inner surface
of the shell is thin and translucent at the margins grading into a pink
color elsewhere. Could be known as Unio acutissimus or Unio rubellinus.
Found in the Luxapalila Creek, Buttahatchee and Sipsey Rivers in the Tombigbee
River drainage, headwaters of the Sipsey Fork (Brushy and Rush Creeks)
in the Black Warrior River drainage, and Conasauga River.
Coosa moccasinshell (Medionidus parvulus)
Bivalve rarely beyond 1.6 inches in length. The shell is thin and fragile.
External color is yellow-brown to dark brown with fine green lines. The
inner surface of the shell is blue, sometimes with dark pink spots. Could
be known as Unio parvulus. Found in the Cahaba River, Sipsey Fork
of Black Warrior River drainage, and Choccolocco Creek, Chatooga, Conasauga,
and Little Rivers in the Coosa River drainage as well as the Coosa River
Southern Clubshell (Pleurobema decisum)
Bivalve up to 2.8 inches long with a thick shell. External color is yellow
to yellowish-brown sometimes with green lines or spots when young. Could
be known as Unio decisus, Unio anaticulus, Unio crebrivittatus,
or Unio pallidovulvus. Once found in every major stream system in
Mobile River drainage except for the Mobile Delta. Now found in Bogue Chitto
Creek in the Alabama River drainage, Buttahatchee, East Fork Tombigbee,
and Sipsey Rivers in the Tombigbee River drainage, and Chewacla Creek in
the Tallapoosa River drainage.
Southern Pigtoe (Pleurobema georgianum)
Bivalve occasionally exceeding 2.4 inches in length. External color is
yellow to yellow-brown with many dark growth lines. Small specimens may
have green spots at the growth lines near the hinge. The inner surface
of the shell is white. Could be known as Unio georgianus. Once found
in the Coosa River drainage. Now found in widely scattered areas of the
Coosa River drainage and in the Conasauga River.
Ovate Clubshell (Pleurobema perovatum)
Bivalve rarely larger than 2.0 inches in length. External color is yellow
to dark brown with occasional broad green lines. The inner surface of the
shell is white. Could be known as Unio perovatus, Unio nux,
Unio cinnamonicus, Unio pinkstoni, Unio concolor,
Unio flavidulus, or Unio johannis. Found in Buttahatchee
and Sipsey Rivers in the Tombigbee River drainage, Blackwater Creek and
Locust Fork in the Black Warrior River drainage, and Chewacla Creek in
the Tallapoosa River drainage.
Triangular Kidneyshell (Ptychobranchus greeni)
Bivalve reaching 4 inches in length. External color is pale yellow when
young aging to yellow-brown and sometimes with fine, wavy or broken green
lines. Could be known as Unio greenii, Unio brumbleyanus,
Unio brumbyanus, Unio foremanianus, Unio woodwardius,
Unio woodwardianus, Unio trinacrus, Unio flavescens,
and Unio simplex. Found in the headwaters of the Sipsey Fork and
Little Warrior River of the Black Warrior River drainage and in the Conasauga
River in the Coosa River drainage.
All these mussels are found on stable gravel and sandy-gravel bottoms
where water quality is excellent. Larva (glochidia) are released into the
water and must attach as a parasite to a host fish species. There they
develop into a juvenile mussel and eventually release the fish, falling
onto a suitable bottom. Specific life histories attributes including hosts,
duration of the parasitic stage, and water temperature interactions are
unknown for these mussel species. Because of tremendous environmental variation
in shell characters, freshwater mussels were taxonomically split into many
small groups that have since been found to not represent full species.
Older species names have been lumped together under new taxonomic treatements.
Habitat modifications, sedimentation, and water quality degradation
are major threats to all these mussels. None will tolerate impoundments.
Loss of native host fish, reduction of water flow, streambed erosion, water
chemistry changes, pollution, dredging and increased turbidity are additional
threats. In the past, freshwater mussels were used to punch out pearl buttons.
Today, many are cut into "pearl seed" used as the central portion of pearls
in Japanese production.
It is unlawful to "take" these federally protected species. "Take" is
the act of, or attempt to, harm, harass, pursue, hunt, shoot, wound, kill,
trap, capture, or collect a protected species. Prohibited acts include
direct and indirect adverse changes in habitat. If you have any questions
or concerns please contact the USDI Fish and Wildlife Service Field Office
at Brunswick, GA (Ph. 912-265-9336).