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Freshwater Mussels

Life Historyfreshwater mussel

  • Freshwater mussels live in rivers, streams and lakes and have a unique life cycle.
  • Freshwater mussel larvae, called glochidia, must attach to the gills or fins of a fish to complete metamorphosis to the juvenile life stage.
  • Female mussels use mimicry to lure in fish. Glochidia are packaged to look like prey items such as small fish, black fly larvae, or crayfish. When host fish try to eat these "lures", the packets break open and glochidia attach to the fish's gills.
  • Each freshwater mussel species has a unique relationship with 1 or a few fish species that serve as the host. For example, mussel species that live in riffles use small fish like minnows or darters while species that live in large rivers or lakes might use largemouth bass or catfish.
  • Their relationship with fish allows mussels to hitch a ride upstream (or downstream) and into habitats that could not be reached by these microscopic organisms if they were simply released into the water.
  • Freshwater mussels act as natural filters, cleaning up streams and rivers while filtering food from the water. Along with food, they remove sediment from the water column making it available for aquatic insects and other bottom dwelling species.

Statusfreshwater mussel life cycle

  • Of the nearly 300 freshwater mussel species found in North America, 70 are listed as either threatened or endangered under the Endangered Species Act of 1972.
  • Many other species are declining where there were once healthy populations or have been locally extirpated due to habitat degradation, poor water quality, and barriers to fish passage.


  • After a number of species were listed as threatened or endangered, researchers made discoveries about freshwater mussel life cycles, tolerances, and distribution. However, there are still many mysteries about freshwater mussels yet to be unraveled.
  • Managers are working to improve water quality, reduce sedimentation, and improve fish passage in rivers and streams where mussels are imperiled.
  • Since the 1990's federal, state, and university aquaculture facilities have discovered techniques for holding mussels in captivity and propagating juvenile mussels.
  • As habitat is improved and protected, and dams are removed, biologists hope to reintroduce freshwater mussels into historic habitat and augment populations where they have declined. An increase in freshwater mussels in our streams and rivers would lead to cleaner water and healthier ecosystems.
Last updated: February 18, 2016
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