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Barnegat Bay is home to blue mussels (Mytilus edulis) and Atlantic ribbed mussels (Geukensia demissa)



Mussels are bivalves and like clams and oysters, their shells consist two halves or valves.

They are filter feeders, feeding by opening their shells and using the cilia attached to their gills to draw water and food particles into their mouths.

Blue mussel                        Mytilus edulis

Blue mussels live in intertidal areas and inlets of Barnegat Bay attached to rocks and other hard substrates by strong (and somewhat elastic) thread-like structures called byssal threads.  These are secreted by byssal glands located in the foot of the mussel.

 Unlike clams, which feed by drawing in water and nutrients through an incurrent siphon and then expelling wastes using an excurrent siphon, mussels feed while submerged at high tide, opening their shells and using the cilia attached to their gills to propel water and food particles into their mouths. At low tide, the shells close.

Blue mussels survive above the waterline at low tide by closing their valves and trapping in water and and function without a fresh supply of oxygen.  Once closed, the movement of cilia is decreases or is suspended to conserve stored oxygen in their cells. 

The incoming tide submerges them again and the valves open.  built-up carbon dioxide is released and a fresh supply of oxygen as well an nutrients become available and they resume filtering until the cycle is repeated at the next low tide.

It should be noted that not all mussels live above the low tide line so they are submerged most if not all of the time so the process described above is not always necessary.

Atlantic ribbed mussel              Geukensia demissa

Atlantic ribbed mussels are relatively large with adults grow to about four inches in length. They live in salt marshes and flats along the shoreline of the bay and are  tolerate to fluctuation and variations in their environment (temperature and salinity).

They are usually found half-buried in mud or attached to marsh grass roots or other surfaces by strong, thread-like strands secreted from the mussel's byssus gland.


Ribbed mussels have a glossy, ribbed shell that varies in color from olive or yellowish-brown to black. The Interior of the shell is iridescent blue to silvery white.

They are filter feeders that feed during high tide or otherwise submerged.  They open their shells slightly to draw in water, filtering out algae and other particles.

Ribbed mussels do not burrow completely into the muddy or sandy bottom but remain partially exposed.  The gills are lined with cilia, which remove oxygen from the water, and trap plankton and organic matter. Particles of organic nutrients are processed into inorganic matter by the ribbed mussel. The inorganic material is recycled back into the mud. This concentrated inorganic material helps to enrich the surrounding mud and contributes to salt marsh growth (living shoreline).

Fun Fact - Although ribbed mussels are edible, they are tough and do not taste as good as the popular blue mussel

Ribbed mussels spawn 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.   They can live 15 years or longer.

Not So Funny Fact -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.