Clubshell

Pleurobema clava

Description

The clubshell has a shell length of up to about 3 in (7.6 cm). The shell is wedge-or triangular-shaped, solid, and its peak (or umbo) is rather pointed and fairly high. The exterior surface is colored bright-yellow to brown, with bright-green, blotchy rays. The inside of the shell (nacre) is pearly white.

Behavior

The specific food habits and reproductive biology of the clubshell are not known, but are likely similar to those of other freshwater mussels. As such, they probably filter-feed on organic particles, algae, and minute animals, which are siphoned out of the water column. During reproduction, the females take in sperm released into the water by males, so that fertilization occurs internally. Fertilized eggs remain in the gills until they hatch into tiny larvae, which are released into the water. The larvae are parasites that attach and form cysts on the gills or fins of a fish host. The larvae metamorphosize and settle to the riverbed, and thereafter lead a sedentary lifestyle.

Habitat

The clubshell inhabits small rivers and streams, where it lives in clean sand and gravel. It typically occurs buried in clean, loose sand to a depth of 2-4 in (5-10 cm).

Distribution

The historical range of the clubshell included Alabama, Illinois, Indiana, Kentucky, Michigan, Ohio, Pennslyvania, Tennessee, and West Virginia.

Threats

The clubshell was once a widespread and abundant bivalve in most of its range. It existed through much of the Ohio River basin in the Allegheny, Green, Kanawha, Kentucky, Licking, Little Kanawha, Mississinewa, Ohio, Salt, Scioto, Tennessee, Tippecanoe, Vermillion, Wabash, and White Rivers. It was also found in the Maumee River basin and tributaries in western Lake Erie (Huron River and River Raison). The clubshell is now enormously reduced in range and abundance, and is only known from 12 streams in Indiana, Michigan, Ohio, Pennsylvania, and West Virginia. Its recent distribution represents a range reduction of more than 95%. The decline of the clubshell has been caused mostly by habitat destruction and damage due to the construction of dams and impoundments, channelization, loss of riparian habitat, and siltation with soil eroded by from poor land uses. Water pollution with organic matter, nutrients, and toxic chemicals from discharges of cities and towns, industries, coal mines, and reservoirs also have impacted the rare club-shell. The invasion of the non-native, very competitive zebra mussel (Dreissena polymorpha ) is another potential threat to the clubshell and other native bivalves.

Conservation and Recovery

Conservation and enhancement of the clubshell requires management to restore some of its critical areas through the repair of riparian habitat and the control of non-point and point-source pollution. Research is needed to identify the habitat needs of the clubshell and its fish hosts, and to develop methods of captive-breeding and reintroduction to wild habitats. Additional field surveys are needed to assess and monitor the condition of existing populations, and to search for suitable habitats for potential reintroduction attempts. It is crucial that the existing habitats are protected from locally incompatible land-uses and aqueous discharges.

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://www.northeast.fws.gov/

U. S. Fish and Wildlife Service
330 Ridgefield Court
Asheville, North Carolina 28806
(704) 665-1195

Reference

U. S. Fish and Wildlife Service. 1993. "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Northern Riffleshell Mussel (Epioblasma torulosa rangiana ) and the Clubshell Mussel (Pleurobema clava )." http://endangered.fws.gov/r/fr93488.html