Atlantic Ribbed Mussel
Geukensia demissa
Atlantic ribbed mussels attach themselves to marsh grass roots and other surfaces with strong, thread-like strands secreted from the byssus gland. Above, Atlantic ribbed mussels attach to marsh grass roots at York River State Park in James City County, Va., on Nov. 18, 2018. (Photo by Will Parson/Chesapeake Bay Program)
An Atlantic ribbed mussel shell is seen at York River State Park in James City County, Va., on Nov. 18, 2018. (Photo by Will Parson/Chesapeake Bay Program)
Atlantic ribbed mussels have glossy, ribbed shells that vary in color from olive or yellowish-brown to black. (Photo courtesy Chris Kratzer/iNaturalist CC BY-NC)
Atlantic ribbed mussels have glossy, ribbed shells that vary in color from olive or yellowish-brown to black. (Photo courtesy astrobirder/iNaturalist CC BY-NC)
The Atlantic ribbed mussel is a bivalve with dark, ribbed shells. It is found in low marshes and mud flats throughout the middle and lower Chesapeake Bay.
Appearance
The Atlantic ribbed mussel grows 2 to 4 inches in length. Its glossy, ribbed shells vary in color from olive or yellowish-brown to black. The shell's interior is iridescent blue to silvery white.
Feeding
Ribbed mussels are filter feeders. During high tide, they opens their shells slightly to draw in water, filtering out algae and other particles.
Predators
The ribbed mussel has many predators, including blue crabs, mud crabs and shorebirds such as rails and willets.
Reproduction and Life Cycle
Spawning occurs once per summer. During spawning season, a ribbed mussel’s gender can be determined by the color of its mantle: females tend to be brownish and males are cream or yellowish. Larvae eventually settle and develop into juveniles. Atlantic ribbed mussels can live 15 years or longer.
Did You Know?
- A ribbed mussel’s age can be determined by counting the ribs on its shells.
- A large group of ribbed mussels can filter all of the water entering a marsh during each tidal cycle. This helps clean and clarify the water.
- Although ribbed mussels are edible, they are tough and do not taste as good as the popular blue mussel.
- During low tide, ribbed mussels close their shells, keeping in waste products that can be toxic to humans. For this reason, you should only collect mussels during high tide.
Sources and Additional Information
- Life in the Chesapeake Bay by Alice Jane Lippson and Robert L. Lippson
- Chesapeake Bay: Nature of the Estuary, A Field Guide by Christopher P. White
- Atlantic Ribbed Mussel – The Assateague Naturalist
- Animal Diversity Web: Geukensia demissa – University of Michigan Museum of Zoology
- Geukensia demissa – Smithsonian Marine Station at Fort Pierce
Quick Facts
Species
Native
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Size
2 to 4 inches in length
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Habitat
Lives in low, regularly flooded marshes and mud flats. Attach themselves to marsh grass roots and other surfaces with strong, thread-like strands secreted from the byssus gland. Clumps of mussels are usually found half-buried in the mud among marsh grasses.
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Range
Found throughout the middle and lower Chesapeake Bay.
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Diet
Filter feeders
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Lifespan
15 years or longer -
Status
Stable
