Department of Environmental Conservation

D E C banner

Mussels & Clams (Mollusca: Pelecypoda)

General Information about Mussels & Clams (Mollusca)
Life history Most freshwater mussels and clams hold their eggs inside their shells until they hatch as larvae. Some kinds of larvae require attachment to a fish host for part of their life stage. Another kind of mussel releases its eggs into the water for fertilization.
Diversity There are about 5 families of freshwater mussels and clams in North America. Two of the families, Corbiculidae and Dreissenidae (zebra and quagga mussels), were introduced and are invasive.
Two shells connected by strong hinge. Shells are a variety of shapes, sizes, and colors; shells may have bumps or ridges. There is no distinct head.
Habitat & Feeding Mussels and clams may be found in lakes, ponds, medium to large rivers, springs, seeps, or small streams. Freshwater mussels and clams are filter feeders (they filter phytoplankton, zooplankton, detritus, and bacteria from the water).
Water quality indicator status Almost all kinds of mussels and clams are sensitive to pollution and environmental stress.
Fun facts
  • Mussels that have parasitic larvae use several techniques to attract a fish host: release large masses of larvae that look like food; look like worms, insect larvae or a small fish. The host fish is not harmed by the larvae.
  • Many different kinds of mussels and clams may live more than 20 years!
image of a east elliptio mussel
East elliptio mussel
image of a rainbow mussel
Rainbow mussel

image of a fat bucket mussel
Fat mucket mussel
image of a pocketbook mussel
Pocketbook mussel