Ring Pink Mussel

Obovaria retusa

Description

This medium-sized mussel, also known as the golf stick pearly mussel, is one of the most endangered of all North American freshwater mussels. Its shell is yellow-green to brown on the outside and dark purple with a white border on the inside.

Behavior

Like other freshwater mussels, the ring pink mussel breeds in the spring. Males release sperm, which are carried by currents downstream to females. As they feed, the females take in the sperm, which fertilize the eggs stored in their gills. Glochidia (larvae) hatch soon after and develop in the female's gills, now modified as brood pouches. After a certain time, the glochidia are released and attach themselves to the gill filaments of host fish (glochidia that do not find host fish sink to the river's bottom and die). When they have grown and developed a shell, the now juvenile mussels detach from the fish and sink to the riverbed. Here, they bury themselves in shoals and riffles, leaving only their shell margins and siphons exposed. Through their siphons, the mussels feed on plankton and other plant matter and expel indigestible particles.

Habitat

This mussel inhabits the sandy but silt-free bottoms of large rivers.

Distribution

Its current distribution includes stretches of three rivers in Tennessee and Kentucky: the Tennessee, Cumberland, and Green Rivers. Total population figures are unavailable.

Threats

The ring pink mussel is in grave danger of extinction, because all of the known populations of the species are apparently too old to reproduce. This mussel was once found in several major tributaries of the Ohio River, including those that stretched into Alabama, Illinois, Indiana, Ohio, Pennsylvania, and West Virginia, so its current limited range signals a major decline in the species. As with many other freshwater mussels, the ring pink mussel's decline can be blamed on human manipulation of its habitat. Damming has historically been the most significant factor, but now the main threats to the surviving populations are water pollution, dredging, and channel maintenance.

Conservation and Recovery

Unless undiscovered, viable populations of the ring pink mussel exist, the future of this species in the wild is uncertain.

Contact

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

Reference

U. S. Fish and Wildlife Service. 1991. "Ring Pink Mussel Recovery Plan." U. S. Fish and Wildlife Service, Atlanta, Georgia.