Endangered Species
Midwest Region



Map of Region 3 Minnesota Wisconsin Michigan

Connect With Us

Facebook icon


Flickr icon




Twitter icon


YouTube icon



Buy Duck Stamps icon Endangered Species Day icon

Great Lake Restoration Initiative logo

Pink Mucket (Lampsilis orbiculata)

Fact Sheet

pdf version


photo of pink mucket pearlymussel

New populations of this mussel have been discovered in the Ohio River after an absence of 75 years, indicating that water quality in this region has improved in recent years.


Habitat: 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.


Behavior: Reproduction requires a stable, undisturbed habitat and a sufficient population of fish hosts to complete the mussel's larval development. When the male discharges sperm into the current, females downstream siphon in the sperm in order to fertilize their eggs, which they store in their gill pouches until the larvae hatch. The females then expel the larvae. Those that manage to find a fish host to clamp onto by means of clasping valves, grow into juveniles with shells of their own. At that point they detach from the host fish and settle into the streambed, ready for a long (possibly up to 50 years) life as an adult mussel.


Why It's Endangered: 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 riverine 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.


Created November 1997


Back to Freshwater Mussels




Last updated: April 14, 2015