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A brownish yellow mussel shell with white abrasions
Information icon Photo by Monte McGregor, Center Mollusk Conservation, Kentucky DFWR.

Littlewing pearlymussel

Pegia fabula


The little-wing pearly mussel is small, not exceeding 1.5 inches in length and 0.5 inches in width. The shell’s outer surface (periostracum) is usually eroded, giving the shell a chalky or ashy white appearance. When the periostracum is present, the shell is light green or dark yellowish brown with dark rays of variable width along the shell’s anterior surface.


The littlewing pearly mussel inhabits cool-water streams in the Cumberland and Tennessee River basins that are small to medium in size, low turbidity, and have a high to moderate gradient. It may be found in riffles lying on top of the substratum, buried in or on top of the substratum in the transition zone between a pool and riffle, or buried beneath boulders.

A small mussel partially buried in sand
A littlewing pearlymussel burrowed in the stream substrate. Photo by Monte McGregor, Center Mollusk Conservation, Kentucky DFWR.


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 little-wing pearly mussel was historically widespread but uncommon in the smaller tributaries of the upper Cumberland and Tennessee River basins in Alabama, North Carolina, Kentucky, Tennessee, and Virginia.

  • Cumberland River System
    • Kentucky
      • Rockcastle River: Laurel and Rockcastle Counties
      • Horse Lick Creek: Jackson and Rockcastle Counties
      • Buck Creek: Pulaski County
      • Pitman Creek: Pulaski County
      • Big South Fork of the Cumberland River: McCreary and Wayne Counties
      • Little South Fork of the Cumberland River: McCreary and Wayne Counties
      • West Fork of the Red River: Todd County
    • Tennessee
      • Cane Creek: Van Buren County
      • Collis River: Warren
      • Stones River: Rutherford County
  • Tennessee River System
    • Alabama
      • Blue Water Creek: Lauderdale County
    • Tennessee
      • South Fork of the Holston River: Sullivan County
      • Elk River at Estell Spring: Franklin County
      • Duck River: county not known
    • Virginia
      • South Fork of the Holston River: Washington County
  • Middle Fork of the Holston River: Smyth County
    • North Fork of the Holston River: Smyth and Washington Counties
    • Big Moccasin Creek: Scott County
    • Clinch River: Tazewell County
    • Copper River: Scott County
    • Flag Pond: Lee County
    • Wallen’s Creek: Lee County
    • Powell River: Lee County
  • North Carolina
    • Valley Creek: Cherokee County
  • French Broad River: State and county not known

Current range

The species continues to be rare and only a few individuals have been observed over the past few years. The littlewing pearlymussel is currently restricted to six watersheds in Kentucky, Tennessee, North Carolina, and Virginia: Big South Fork of the Cumberland River, Rockcastle River, Cane Creek, Clinch River, North Fork Holston River, and Little Tennessee River. The only viable population is believed to be in the Big South Fork of the Cumberland River.

Counties Where the Species is Present or Believed to Occur

  • Alabama: Lauderdale and Limestone counties
  • Kentucky: Jackson, Logan, McCreary and Rockcastle counties
  • North Carolina: Macon and Swain counties
  • Tennessee: Bedford, Bledsoe, Coffee, Fentress, Franklin, Greene, Grundy, Hawkins, Marion, Moore, Pickett, Rutherford, Scott, Sequatchie, Sullivan, Van Buren, Warren, Washington and White counties
  • Virginia: Bland, Bristol, Buchanan, Dickenson, Grayson, Lee, Norton, Russell, Scott, Smyth, Tazewell, Washington, Wise and Wythe counties
A shallow river with rocky shore and mature trees
Habitat in the Big South Fork of the Cumberland River. Photo by Monte McGregor, Center Mollusk Conservation, Kentucky DFWR.

Conservation challenges

The main threats to the species are habitat loss and water quality deterioration from impoundments, industrial and municipal pollution, acid mine drainage, and siltation; However, some losses are apparently due to other changes in water and habitat quality since some populations have been extirpated from stream reaches that still contain mussel communities.

Most remnant littlewing pearlymussel populations are small and isolated, which restricts the natural interchange of genetic material among populations. Small population sizes increases the chances of genetic variation loss due to genetic drift. The loss of genetic variation could adversely affect, over time, the species’ ability to evolve and respond to natural habitat changes.

Recovery plan

Download the 1984 Recovery Plan.

The goal of the recovery plan is to maintain and restore of the littlewing pearlymussel to a significant portion of its historical range in the Cumberland and Tennessee River systems, and to remove the species from the endangered species list.

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

Designated critical habitat

No critical habitat is designated for this species.

Additional resources

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.

  • We're sorry but an error occurred. Visit the Federal Register to conduct your own search.

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