Common Clam Worms

Working at the oyster bar station for Estuary, at Seining, or even just pulling up ropes from the dock we’ll find the common clam worm. This is a short introduction to clam worms:

• Common Clam Worm (Alitta succinea)–is a polychaete worm (polychaete means a number of bristles), or bristle worm, with a ringed and segmented body. Their bodies are reminiscent of centipedes with hundreds of outwardly extending parapoda or paddle like appendages.
• The parapoda, or paddle like appendages, are covered in sensory bristles that can “taste” chemical smells in the water, sense current changes, and act as feelers.
• All of the parapoda on the worm allow the worm to swim in the water. Common clam worms are both free swimming and bottom dwelling, though they only swim at night during breeding season.
• Most of the time clam worms live in U shaped burrows in the sediment or among patches of barnacles.
• Clam worms can reach up to 6″ long but typically here in the Bay they’re about 1″ or less.
• You can tell the head from the rear of the animal because it’s head is lighter colored reddish brown while the rear is dark brown.
• Their head consists of four eyes, two palps or mouth parts, and eight tentacles, yes tentacles! These tentacles can be used for gripping or grabbing.
• Clam worms feed mostly on other worms and algae.
• To feed they extend their proboscis, which has a hooked shape to the jaw, which snares the prey and then is used to draw it into their mouth using the help of their small tentacles and palps.

(http://www.glf.dfo-mpo.gc.ca/Gulf/By-The-Sea-Guide/Tidal-Mudflats)

• During the breeding season, in the Spring and early Summer, their parapoda swell or enlarge, enabling them to swim in the water column. They then release their sperm and eggs into the water. Their fertilized eggs develop into larvae then become free swimming zooplankton. The adults die after breeding.
• Common clam worms have one unique defense. If threatened they can secrete a mucus cocoon around themselves, which hardens and then becomes a protective shell.
• Clam worms are an important part of the Chesapeake Bay food web because they are predators of other invertebrates, consume algae, and are a food source for many other organisms such as crabs, fish, and shrimp.
• Clam worms are also important bioindicators because they consume algae and sediment along the bottom of the estuaries. Their bodies accumulate toxins through their benthic feeding, and this may travel up the food web. Scientists often study bristle worms as pollution indicators.

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