The Body Builders of Little Assawoman Bay

In our area, oysters get all the glory for cleaning our bays. But they aren’t the only mollusks in the ring. For filtering water and controlling erosion, Atlantic Ribbed Mussels do a lot of heavy lifting.

Their name comes from the fact that they have ridges, or ribs, on their shells as opposed to the smooth shells of Blue mussels. Atlantic ribbed mussels can live up to fifteen years. You can determine their age by counting the ribs on their shells.

You’ll find thick aggregates of Atlantic ribbed mussels along the muddy banks of the salt marshes in our inland bays. They attached themselves to the roots of the salt marsh grasses (and each other) with strong, silky fibers called byssal threads. Made of collagen, just one of these tiny threads is strong enough to hold a gallon of milk. Its composition is like that of our Achilles’ tendon, but five times stronger. One mussel produces a bundle of fifty to one hundred of these strands to hold it in place. This, in turn, holds the salt marsh in place, protecting it from wave action and erosion. Also, the mussel’s waste fertilizes salt marsh grasses, contributing to the growth of this important ecosystem.

While an adult, wild oyster filters over three times more water per day than a mussel (50 gallons versus 15 gallons), mussels are more numerous. They can reach densities of up to 3,000 per square meter! They are hardier than oysters and can adapt to a wide range of salinities, making them perfectly at home in the brackish waters of Little Assawoman Bay.

But can you eat them??

This is the question nearly everyone asks once they see the plentiful mussels embedded in the muddy banks of the bays. If you were about to die of starvation, maybe, but it’s not recommended. According to The Chesapeake Bay Program, they are very tough compared to their tasty cousins, Blue mussels. And, if you collect them at low tide when they are exposed, they can be toxic to humans.

So the next time you paddle through the salt marshes, notice the vast numbers of these strong, silent types. They’re constantly at work cleaning our bays.

Information for this blog post came from:,and%2For%20to%20Spartina%20culms.

The Byssal Thread: Mighty Fiber and Future Trend?,matter%20by%20the%20ribbed%20mussel.

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