Thursday, July 15, 2010

Geukensia demissa

The Atlantic ribbed mussel is a common mussel species found on much of the shoreline of the eastern United States (from about Maine to northern Florida). They are an important part of the Marshy tidal ecosystems and filter feed bacteria, heavy metals and algae from the water column.

Mussels are bivalves (meaning two shells) which are a family of mollusks. This puts them into relationship with snails, octopuses, squids and cuttlefish (in addition to a few other smaller families). Like all other bivalves (clams, oysters) these ribbed mussels have a muscular “foot” with which they are capable of crawling through the sediment. They typically will remain in one spot, however, unless their ecosystem changes drastically enough.

In fact mussels have the habit of holding themselves fast to stable objects such as grasses, rocks, other bivalves as well as docks and other man-made objects. They do this with something called “byssal” or “byssus” threads, strong, sticky threadlike structures secreted from their foot. This is what keeps mussel “clumps” held together and is both a strategy for keeping safe from predators (their shells aren’t as thick and hard as their cousins the clams) as well as for preventing themselves from being swept away by waves and tides. This also puts them in a mutualistic (symbiotic) relationship with marsh grass. The grass provides the mussel with an anchor to attach to and the mussels provide fertilizer in the form of waste products.

These mussels are typically found in marshy areas with just their very tops poking out of the mud. I found these in West Dennis on Cape Cod over the weekend. I have also seen these mussels in other marshes in Massachusetts.

This is a hilarious quote from the Chesapeake Bay field guide: “While the Atlantic ribbed mussels are edible, they have an unpleasant taste, unlike the popular blue mussel.”

Edible yes. Pleasant, no.


The Assateague Naturalist:

The EOL:

University of Rhode Island:

The Chesapeake Bay Field Guide:

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