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A brown and black mussel with growth striations sitting on a rock.
Information icon Close-up of endangered mussel from the Ohio River. Photo by Craig Stihler, USFWS.

Pink mucket

Lampsilis abrupta

The pink mucket was listed as endangered in 1976. This species features an elliptical to quadrangular shell. The yellow-brown surface of the shell is smooth except for relatively dark, concentric growth marks and wide greenish rays. The shell is dull in older individuals while younger mussels are glossy. The mussel Males release sperm into the water in late summer or autumn. Females take the sperm, then brood fertilized larvae over the winter in their gill pouches and release them the following spring.

It inhabits shallow riffles and shoals of major rivers and tributaries and is found in rubble, gravel or sand substrates that have been swept free of silt by the current. This species is considered endemic to the Interior Basin and was found primarily in the Tennessee, Cumberland and Ohio River drainages. They have also been collected in the Missouri, Black and Mississippi rivers. They have been documented in 25 rivers and tributaries in 11 states. The greatest concentrations have been found in the Tennessee, Cumberland Osage and Meramec rivers. Although this mussel has been found over a wide geographic area, they have never been collected in large numbers and has always been considered uncommon.

The construction of dams and reservoirs on the major rivers have been possibly the greatest single factor in the decline of the pink mucket. 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. As the many other mussel species heavy loads of silt have been introduced into most watersheds from strip mining, coal washing, dredging and intensive logging. Siltation smothers mussel beds or decreases the abundance of host fish.

As part of a recovery effort, Tennessee and Alabama have designated portions of the Tennessee and Cumberland rivers as mussel sanctuaries.


Adult pink muckets grow three to five inches in length. They are rounded to slightly elongated. The rear end is bluntly pointed in males. Females are shorter and may be nearly square. The pink mucket shell is thick, inflated and smooth. Growth-rest lines produce ridges and dark-stained grooves. The outer layer of the shell is yellowish-brown to chestnut-colored in mature individuals. Broad, faint, green rays may cover the shell but are usually absent from adult shells.

Beaks (raised structures located externally near the hinge of the shell) are slightly raised above the hinge line. Beak sculpture, which is often difficult to discern, consists of six to 10 fine, wavy, double-looped bars. The teeth (located dorsally within the shell) are large and well developed. The shell’s inner lining (nacre) is white to a light salmon or pink and commonly salmon to orange in the beak cavities.


This mussel is found in mud and sand and in shallow riffles and shoals swept free of silt in major rivers and tributaries. This mussel buries itself in sand or gravel, with only the edge of its shell and its feeding siphons exposed.

A forested island
Ohio River Islands Refuge habitat of the pink mucket. Photo by Craig Stihler, USFWS.


The pink mucket feeds on suspended plankton and on bacteria and organic matter in substrate.

Historic range

The species historical range included Alabama, Arkansas, Illinois, Indiana, Kentucky, Louisiana, Missouri, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia.

Current range

The pink mucket is known to or is believed to occur in Alabama, Georgia, Illinois, Kentucky, Louisiana, Mississippi, Missouri, Ohio, Tennessee, Virginia, West Virginia. Download a list of U.S. counties in which this population is known to or believed to occur.

National wildlife refuges that support populations

Conservation challenges

Dams and reservoirs have flooded most of this mussel’s habitat, reducing its gravel and sand habitat and probably affecting the distribution of its fish hosts. Impoundments are fatal to most river-dwelling mussels; one researcher counted 45 mussel species in a river before the construction of a dam. Four months after the dam was completed, he could find none.

Erosion caused by strip mining, logging and farming adds silt to many rivers, which can clog the mussel’s feeding siphons and even bury it completely. Other threats include pollution from agricultural and industrial runoff. These chemicals and toxic metals become concentrated in the body tissues of such filter-feeding mussels as the fanshell, eventually poisoning it to death.

Recovery plan

Download the 1985 recovery plan.

Partnerships, research and projects

The Kentucky Department of Fish and Wildlife Resources Center for Mollusk Conservation culture the pink mucket at their facility in Frankfort, Kentucky. Once they have grown for a few weeks they are brought to Wolf Creek National Fish Hatchery, where they are placed into cages built specifically for mussel propagation. These cages are placed in floating racks in Lake Cumberland where they will reside for one to two growing seasons (April to October). Staff at Wolf Creek monitor cages weekly, brushing off excess algae to allow optimal food flow through. Once the juveniles have been deemed big enough they are released back to their natural habitat.

Dark brown mussels being propagated in plastic buckets
Juvenile pink mucket being reared in the raceway upweller at the Kansas City Zoo. Photo by Chris Barnhart, Missouri State University.

How you can help

  • Protect waterways, keep clean of garbage and other liquid pollutants.
  • Volunteer time to various organizations aimed at habitat restoration projects, i.e Kentucky Wild programs.

Subject matter experts

  • Kentucky Department of Fish & Wildlife Resources Center for Mollusk Conservation

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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