Notes On The Clam Worm


In tracking the timing of flower and leaf emergence in early spring, one will notice that a majority of the species getting a head start on the growing season are non-natives.A mentioned in previous columns, the first plants to flower in the spring are the crocuses, snowdrops and daffodils, joined a bit later by our native red maple. Two ubiquitous non-natives—a ground cover called periwinkle and the bright-yellow flowered shrub called forsythia—are blooming now.

Among the plants sprouting leaves this month are barberry, Japanese honeysuckle, privet, crabapple, sweet woodruff, larch, Norway maple, willow and skunk cabbage. With the exception of the latter two, these are non-natives.

Down at the Accabonac Harbor marsh edge, I found the clam worm (Nereis virens), an important resident of the marsh and estuary benthic community. This is also an important type of fish bait that supports a commercial fishery in Maine.

Although measuring the length of a creature that moves by elongating itself is an imprecise task, the specimen I found was approximately 6 inches long when immobile in my hand. This is very small by clam worm standards: its 200 segments can span up to 3 feet in length!

Each segment is adorned with a pair of foot appendages called parapodia that are tipped with bristles. These are used for respiration and locomotion, both walking over and through the bottom sediments and swimming.

The head has several pairs of sensory antennae somewhat resembling ears, and a pair of shorter, blunt projections called palps resembling eyes (its actual eyes are four tiny black dots located on the top of the head that can only discern light and dark) that are also sensory receptors.

As I watched it in my hand, its harmless-looking fleshy mouth slowly everted to reveal a pair of formidable, black claw-like pincers. The clam worm is a voracious predator, leaving its mucous-lined burrow at night in search of other worms, crustaceans and small fish, and to tear off pieces of carrion and algae with its hard pincers. The latter are strong enough to crush small bivalves, and can inflict a painful bite if handled carelessly.

In turn, the clam worm is an important prey species for many marine organisms and birds, and they are a very important component of the salt marsh and estuary ecosystem. Their population can reach astonishing densities, as much as 1,000 per square meter of bay bottom. Bottom-feeding fishes such as skates and drum, crabs and shorebirds are known predators. A study in the Gulf of St. Lawrence found that, between late May and mid-July, up to 40 percent of the diet of the common eider consisted of clam worms.

One of my favorite coastal reference books has this to say about the clam worm: “The observer who thinks of worms as ugly creatures may have a change of heart when watching a 3-ft. Nereis virens as it swims with gracefully undulating movements, its body an iridescent blue green dappled with red or gold and glinting in the sunlight.” (From A Sierra Club Naturalist Guide to the Middle Atlantic Coast by Bill Perry.)

The next nature paddle is on Saturday, May 9. We will note more signs of spring as we paddle the upper section of the Peconic River. Details at

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