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Pink mucket pearly mussel [Lampsilis orbiculata]
The pink mucket pearly mussel has an elliptical shell that
is 4 in. long, 2.4 in. wide, and 3 inches high. Young mussels have a yellow
to brown shell that is smooth and glossy with green rays and growthmarks,
while older specimens are a dull brown. This mussel is a unique long-term
breeder in which male pink muckets release sperm in late summer or fall
that fertilizes larvae in females which is incubated until the following
spring. The pink mucket pearly mussel inhabits shallow riffles or shoals
in areas of gravel, rubble, or sand substrates that have been swept free
of silt by the current. (Silt clogs the siphons in which mussels use to
strain water for nutrients.)
In the past, populations of this mussel were found in 25
rivers and tributaries in 11 states. Currently, the pink mucket is known
in 16 rivers and tributaries from 7 states with the greatest concentrations
in the Tennessee (TN, AL) and Cumberland (TN, KY) rivers, and in the Osage
and Meramec rivers (MO). However, large numbers of this species have never
been collected and it has always been considered rare. Smaller populations
have been found in the Clinch River (TN), Green River (KY), Kwanawha River
(WV), in the Big River, Black and Little Black, Gasconde rivers (MO),
and in Current and Spring rivers (AR).
The pink mucket has declined in range and numbers due to
dam and reservoir construction that has changed natural river flow, water
temperatures, and oxygen and sediment contents. In addition, heavy loads
of silt from strip mining, coal washing, dredging, and logging, along
with agricultural runoffs have significantly deteriorated water quality
essential for mussel reproduction and feeding.
In attempts to restore pink mucket habitat, the states of
Tennessee and Alabama have designated mussel sanctuaries in parts of the
Cumberland and Tennessee Rivers and have sucessfully reproduced populations
at these locations. Recently, live specimens were discovered in the upper
Ohio River where the pink mucket had not been found for 75 years. Scientists
associate this to improved water quality in the area and believe that
this species could be similarly reintroduced to areas in which the pink
mucket has been extirpated if water quality is restored.
Matthews, J.R. (ed.), The Official World Wildlife Fund Guide to Endangered
Species, Beacham Publishing Inc, Washington, DC. Vol. II, pp. 985-986.
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