Pink Mucket Pearlymussel

Lampsilis abrupta

Description

The pink mucket pearlymussel, Lampsilis abrupta, features an elliptical to quadrangular shell that attains a length of 4 in (10 cm), a width of 2.4 in (6 cm), and a thickness of 3 in (8 cm). The yellow to brown surface of the shell is smooth except for relatively dark, concentric growth marks and wide greenish rays, which are more prominent in juveniles. The shell is glossy in younger specimens and dull in older individuals. The valves are thick, heavy, and unsculptured.

Behavior

The pink mucket is a long-term breeder (bradytictic). Males release sperm into the water in late summer or autumn. Females take in the sperm then brood fertilized larvae (glochidia) over winter in gill pouches and release them the following spring.

For more on the behavior and diet of freshwater mussels, see the Upland Combshell (Epioblasma metastriata ) entry.

Habitat

The pink mucket pearlymussel inhabits shallow riffles and shoals of major rivers and tributaries. It is found in rubble, gravel, or sand substrates that have been swept free of silt by the current.

Distribution

This pearlymussel is considered endemic to the Interior Basin and was found primarily in the Tennessee, Cumberland, and Ohio River drainages, although specimens have been collected from the Missouri, Black, and Mississippi Rivers. This mussel has been documented from 25 rivers and tributaries in 11 states—West Virginia, Pennsylvania, Ohio, Illinois, Indiana, Kentucky, Tennessee, Alabama, Arkansas, Missouri, and Iowa. Populations appear to have been extirpated from the northern portion of the range (Ohio, Indiana, and Illinois).

As of 1991, the pink mucket pearlymussel was known from 17 rivers and tributaries, with the greatest concentrations in the Tennessee, Cumberland, Osage, and Meramec Rivers. Although it is found over a wide geographic area, this mussel was never collected in large numbers and has always been considered uncommon.

Populations occur in the Tennessee River below Pickwick, Wilson, Guntersville, and Watts Bar Dams (Tennessee and Alabama); above New Hope on Paint Rock River (Alabama); in the Clinch River below Melton Hill Dam (Tennessee); in the Cumberland River at Bartletts Bar, Cotton Bar, Rome Island, and Carters Island (Kentucky and Tennessee); in the Green River (Butler County, Kentucky); and in the Kanawha River below Kanawha Falls (West Virginia). Populations west of the Mississippi River are found in the Osage River below Bagnell Dam, in Missouri; in several other Missouri rivers: the Meramec, Big, Black, Little Black, and Gasconade; and in Current and Spring Rivers (Arkansas). In 1990 authorities identified a new population site in the Ohio River, bordering West Virginia; another new population was discovered in 1991 in a reach of the lower Elk River near Blue Creek (West Virginia), which is part of the species' historic range.

Threats

Possibly the greatest single factor in the decline of the pink mucket pearlymussel has been the construction of dams and reservoirs on the major rivers for flood control, navigation, hydroelectric power production, and recreation. Impounding the natural river flow eliminates those mussels and fishes that are unable to adapt to reduced and sporadic flows, altered water temperatures, and seasonal oxygen deficiencies. Although a few dams have actually created downstream habitat for the pink mucket, in most cases this has come at the expense of inundating large stretches of upstream habitat.

Heavy loads of silt have been introduced into most watersheds from strip mining and coal washing, dredging, and intensive logging. Deforestation and poor agricultural practices are probably responsible for the loss of many native mussel populations, particularly in the midwestern states. Siltation smothers mussel beds or decreases the abundance of fish hosts, which are necessary to complete the mussel's life cycle.

Conservation and Recovery

The states of Tennessee and Alabama have designated portions of the Tennessee and Cumberland Rivers as mussel sanctuaries. Because of these protections the pink mucket pearly mussel is again reproducing well in localized areas. In the late twentieth century, live specimens were discovered in the upper Ohio River, where this species had not been collected for 75 years. Scientists took this discovery as evidence of improving water quality in this region.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1 Federal Drive
BHW Federal Building
Fort Snelling, Minnesota 55111
Telephone: (612) 713-5360
http://midwest.fws.gov/

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

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035-9589
Telephone: (413) 253-8200
Fax: (413) 253-8308
http://northeast.fws.gov/

References

Fuller, S. 1974. "Clams and Mussels." In Pollution Ecology of Freshwater Invertebrates, edited by Hart and Fuller. Academic Press, New York.

Isom, B. G. 1969. "The Mussel Resources of the Tennessee River." Malacologia 7 (2-3): 397-425.

U. S. Fish and Wildlife Service. 1985. "Recovery Plan for the Pink Mucket Pearly Mussel." U. S. Fish and Wildlife Service, Atlanta.