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Endangered Species Program
Conserving and restoring threatened and endangered species and their ecosystems
Ring Pink (Obovaria retusa)
Habitat: This mussel is found in shallow water over silt-free sand and gravel bottoms of large rivers.
Behavior: Reproduction requires a stable, undisturbed habitat and a sufficient population of fish hosts to complete the mussel's larval development. When the male discharges sperm into the current, females downstream siphon in the sperm in order to fertilize their eggs, which they store in their gill pouches until the larvae hatch. The females then expel the larvae. Those larvae which manage to attach themselves to the gills of a host fish grow into juveniles with shells of their own. At that point they detach from the host fish and settle into the streambed, ready for a long (possibly up to 50 years) life as an adult mussel.
Why It's Endangered: Once found in the Ohio River and its large tributaries from West Virginia to Illinois and Kentucky, the ring pink is known today from only two stretches of the Tennessee River and one stretch each of the Cumberland and Green rivers. Dams and reservoirs have flooded most of the mussel's habitat, reducing its gravel and sand habitat and probably affecting the distribution of its host fish. Only 5 populations of this mussel are known to exist, and their advanced age further reduces the chances of successful reproduction. These five populations are geographically isolated from one another as well
Other threats include gravel dredging of rivers (which disturbs habitat) and pollution. A population in the Green River is threatened by water pollution from upstream oil and gas production.
Fact Sheet Created November 1997
Last updated: October 10, 2018