Atlantic Ribbed Mussel
Geukensia demissa

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 attatch 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. 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 are not as popular for eating as blue mussels.
• 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
• Animal Diversity Web: Geukensia demissa - University of Michigan Museum of Zoology
• Ribbed Mussels - Virginia Institute of Marine Science