PINK MUCKET (PEARLYMUSSEL)

Lampsilis abrupta

SPECIES CODE: F00G I01

STATUS:

On June 14, 1976, the pink mucket (pearlymussel) was designated as endangered throughout its entire range in Alabama, Arkansas, Illinois, Indiana, Kentucky, Louisiana, Missouri, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia (USFWS 1976). A recovery plan addressing the pink mucket was approved in January 24, 1985 (USFWS 1985).

SPECIES DESCRIPTION:

The pink mucket is a medium-sized (reaching up to approximately 100 mm in length) freshwater mussel with a smooth, yellow or yellowish green shell and faint green rays (INHS 1997, VFWIS 2003). The life span of the species exceeds 50 years (VFWIS 2003). Like other freshwater mussels, the pink mucket feeds by filtering food particles from the water column. The specific food habits of the species are unknown, but other juvenile and adult freshwater mussels have been documented to feed on detritus, diatoms, phytoplankton, and zooplankton (Churchill and Lewis 1924). The diet of pink mucket glochidia, like other freshwater mussels, comprises water (until encysted on a fish host) and fish body fluids (once encysted).

REPRODUCTION AND DEVELOPMENT:

The reproductive cycle of the pink mucket is similar to that of other native freshwater mussels. Males release sperm into the water column; the sperm are then taken in by the females through their siphons during feeding and respiration. The females retain the fertilized eggs in their gills until the larvae (glochidia) fully develop. The mussel glochidia are released into the water, and within a few days they must attach to the appropriate species of fish, which they parasitize for a short time while they develop into juvenile mussels. Laboratory studies have confirmed that four of nineteen fish tested are suitable hosts for the pink mucket. These include the largemouth bass (Micropterus salmoides), spotted bass (Micropterus punctulatus), smallmouth bass (Micropterus dolomieu), and walleye (Stizostedion vitreum) (Barnhart 1997). Other reported glochidial fish host species include the sauger (Stizostedion canadense) and the freshwater drum (Aplodinotus grunniens) (USFWS 1985, VFWIS 2003). The pink mucket is unique in that the females possess a spotted mantle flap which may serve to mimic a fish eyespot to attract host fish (USFWS 1985).

RANGE AND POPULATION LEVEL:

The pink mucket has undergone a substantial range reduction. It was historically distributed in 25 rivers and tributaries in the Ohio, Cumberland, Mississippi, and Tennessee River systems. The species is likely extirpated in Ohio, Pennsylvania, and Illinois (NatureServe 2003). Records from 1990 indicate that the species remained in only 16 rivers and tributaries at that time (NatureServe 2003).

HABITAT:

The pink mucket typically inhabits medium to large rivers with strong currents; however, it has also been able to survive and reproduce in areas of impounded reaches with river/lake conditions without standing water (NatureServe 2003, USFWS 1985). Substrate preferences include sand, gravel, and pockets between rocky ledges in high velocity areas and mud and sand in slower moving waters. Individuals have been found at depths up to one meter in swiftly moving currents and in much deeper waters with slower currents (Gordon and Layzer 1989).

PAST THREATS:

Past threats to the species include habitat modification through impoundments, channelization, and dredging operations as well as water quality degradation and commercial over harvestation (NatureServe 2003). A controlled release of mine water discharge dominated by iron in a tributary to the Ohio River supporting habitat for the pink mucket was evaluated to determine potential toxic effects to surrogate mussel and clam species. Instream monitoring of surrogate mussel populations pre- and post-discharge indicated that there was no significant enzymatic effect response 30 days after the release; however, given the demonstrated recovery ability of mine-water exposed clams in laboratory-based studies, it is believed that Ohio River mussels likely experienced a brief period of impaired physiological function (e.g., enzymatic function, growth, and siphoning activity) that was not apparent at the time of post-release monitoring. Bivalve response thresholds for siphoning and bioconcentration were compared to other standardized test responses, and ultimately, results supported a criteria for the bioavailable form of iron for freshwater mussels at 0.37 mg ferrous iron/liter (Milam and Farris 1998). Other threats are discussed in greater detail in the general mussel description.

CURRENT THREATS:

Other current threats to freshwater mussels are well documented in the general mussel description.

CONSERVATION MEASURES:

Exposure Scenario Summary Table for the Pink mucket
Species	Life Stage	Habitat Type	Exposure Route	Diet	Significant Interspecies Relationships
pink mucket	glochidiaasite	contact with water, diet	water (until encysted), fish body fluids (once encysted)	largemouth bass potted bass smallmouth bass walleye sauger freshwater drum
	juvenile / adult	sediment dweller	contact & ingestion of water, diet, sediment	filter feeder (bacteria, algae, detritus, sediment)

LITERATURE CITED:

Barnhart, M.C. 1997. Reproduction and fish hosts of unionid species of concern. Southwest Missouri State Univ., Springfield Dept. of Biology, Missouri Dept. of Conservation, Columbia, MO.

Churchill, E.P., Jr., and S.I. Lewis. 1924. Food and feeding in freshwater mussels. Bull. U.S. Bur. Fish. 39: 439-471.

Gordon, M.E. and Layzer, J.B. 1989. Mussels (Bivalvia: Unionoidea) of the Cumberland River review of life histories and ecological relationships. Biological Report 89(15): 1‑99.

Illinois Natural History Survey. 1997. Species Account, Lampsilis abrupta (Say, 1831), Pink Mucket. Illinois Department of Natural Resources. Champaign, IL. Available http://www.inhs.uiuc.edu/chf/pub/mussel_man/page154_5.html. (Accessed: December 3, 2003).

NatureServe. 2003. NatureServe Explorer: An online encyclopedia of life [web application]. Version 1.8. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: December 3, 2003 ).

Millam, C.D. and J.L. Farris. 1998. Risk identification associated with iron-dominated mine discharges and their effect upon freshwater bivalves. Environmental Toxicology and Chemistry. 17(8): 1611-1619.

U.S. Fish and Wildlife Service. 1976. Endangered Status for 159 Taxa of Animals. Federal Register 41: 24062-24067.

U.S. Fish and Wildlife Service. 1985. Recovery Plan for the Pink Mucket Pearly Mussel (Lampsilis orbiculata). Atlanta, GA. 52 pp.

Virginia Fish and Wildlife Information Service. 060152 Mucket (pearlymussel), pink. Virginia Department of Game and Inland Fisheries. Richmond, VA. Available http://vafwis.org/BOVA/BOOKS/060152.HTM. (Accessed: December 3, 2003).