Fanshell

Cyprogenia Stegaria

• Taxon: Bivalve
• Range: Alabama, Illinois, Indiana, Kentucky, Ohio, Tennessee, Virginia and West Virginia.
• Status: Endangered. Some populations in the French Broad and Holston Rivers are experimental.

Appearance

The fanshell has a medium-sized shell, seldom exceeding 3.2 inches in length. The shell exterior has green rays on a light green or yellow surface ornamented with green mottling. The inside surface of the shell (nacre) is usually silvery white.

Habitat

This mussel species inhabits medium to large rivers. It has been reported primarily from relatively deep water in gravel substrate with moderate current.

Diet

Mussels are filter feeders; they mainly eat phytoplankton, zooplankton, and bacteria suspended in the water. By drawing water inside their shells through a siphon, their gills filter out food and take in oxygen.

Historical range

The fanshell historically occurred in the Ohio River and many of its large tributaries in Pennsylvania, West Virginia, Ohio, Indiana, Illinois, Kentucky, Tennessee, Alabama and Virginia.

Current range

It is believed that reproductively viable populations are now only found in the following three rivers:

1. the Clinch River in Hancock County, Tennessee and Scott County, Virginia;
2. the Green River in Hart and Edmonson counties, Kentucky; and
3. the Licking River in Kenton, Campbell and Pendleton counties, Kentucky.

Counties where the species is present or believed to occur

• Kentucky: Green River in Hart and Edmonson counties; Licking River in Kenton, Campbell, and Pendleton counties; Tygarts Creek in Greenup and Carter counties; Barren River in Allen and Barren counties.
• Tennessee: Clinch River in Hancock County; Cumberland River in Smith County; Tennessee River in Rhea, Meigs, and Hardin counties.
• Virginia: Clinch River in Scott County.
• Ohio: Muskigum River in Morgan and Washington counties; Warhonding River in Coshocton County.
• Illinois: Wabash River in White County.
• Indiana: Wabash River in Posey and Wabash counties; East Fork of White River in Martin County; Tippecanoe River in Tippecanoe County.
• West Virginia: Kanawha River in Fayette County.

Conservation challenges

The distribution and reproductive capacity of this species has been seriously impacted by the construction of impoundments and navigation facilities, dredging for channel maintenance, sand and gravel mining, and water pollution.

How you can help

Individuals can do a number of things to help protect mussels, such as:

• Conserving water to allow more water to remain in streams.
• Using pesticides responsibly, especially around streams and lakes, to prevent runoff into mussel habitats.
• Controlling soil erosion by planting trees and plants to avoid runoff of sediments into freshwater areas.
• Supporting practices for construction and maintenance of unpaved, rural dirt and gravel roads that minimize erosion and connectivity to our rivers and lakes.
• Supporting and follow zebra mussel quarantine, inspection, and decontamination programs to prevent the spread of zebra mussels, an invasive species that competes with native mussels.

Subject matter experts

• Leroy Koch, Fish and Wildlife Biologist, Kentucky.
• Bob Butler, Fish and Wildlife Biologist, North Carolina.
• Stephanie Chance, Fish and Wildlife Biologist, Tennessee.

Designated critical habitat

No critical habitat is designated for this species.

Additional resources

• Mussels and Aquatic Snails, Kentucky Department of Fish and Wildlife Resources: biology and conservation information related to mussels and aquatic snails in Kentucky.
• Freshwater Mollusk Society: the Freshwater Mollusk Conservation Society (FMCS) is dedicated to the conservation of and advocacy of freshwater mollusks, North America’s most imperiled animals.
• The Nature Conservancy in Kentucky: conserving nature to ensure Kentuckians have clean air and water, healthy soils and open spaces to enjoy forever.
• Kentucky Waterway Alliance: advocates for healthy waterways and communities throughout Kentucky.
• Walkerana — The Journal of the Freshwater Mollusk Conservation Society
• Ellipsiana — Newsletter of the Freshwater Mollusk Conservation Society

Federal Register notices

The following Federal Register documents were automatically gathered by searching the Federal Register Official API with this species’ scientific name ordered by relevance. You can conduct your own search on the Federal Register website.

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