Milky Ribbon Worms

A Growing Problem In West

by Laurie Schreiber


“Our goal is to work with
clam harvesters to
identify locations
most impacted.”
– Monique Coombs


ROCKPORT — Milky ribbon worms are wreaking havoc on the flats and consuming soft-shell clams voraciously.

That’s the word from Brunswick-based Maine Coast Fishermen’s Association Seafood Program Director Monique Coombs, who presented an update on the topic at the Maine Fishermen’s Forum in early March.

Over the past year, Coombs said, she worked with the Harpswell Marine Resources Committee to study the worm.

“There are not a lot of experts in the world about these worms,” she said. “The best place to start is to understand what’s going on.”

Coombs said talks with harvesters revealed there is a large presence of milky ribbon worms in the Harpswell area. Harvesters there collected 100 pounds of ribbon worms from just a small area, she said.

“Our goal is to work with clam harvesters to identify locations most impacted,” she said. “We’re also seeking input from anyone, but from clam harvesters specifically, about what we can do with these worms.”

Harspwell, Brunswick, Freeport and Scarborough appear to have a prevalence of milky ribbon worms, she said.

The milky ribbon worm is flat, growing up to 3-4 feet long. Coombs said she’s heard them called “tapeworms” locally. But they’re not tapeworms. She said they have an interesting proboscis, which helps the worm move through mud, and find and consume prey. Clams appear to be optimal prey, she said, but the worms also consume razor clams, quahogs and other worms. The only creatures known to eat milky ribbon worms, she said, are some types of flounder, possibly horseshoe and green crabs, and possibly some birds.

There is little scientific information about the milky ribbon worm, she said. However, one study from Prince Edward Island found that soft-shell clam mortality was 100 percent with milky ribbon worms present. Researchers in that study, she said, also placed the worms and clams in tanks with other species, and found the worms consistently chose the clams over all of the other species.

The worms appear to use chemo-receptors to find the scent of clam meat, she said. PEI research noted the worms appear to eat and hunt in packs, she said.

The worms are natives of Maine, she said. So the question, she said, is whether there is a way to diminish the milky ribbon worm population or else create a market for the creatures. It’s unknown whether they’re edible, she said: It’s been suggested there might be some use for them as bait, or in pharmaceuticals or biomedical research.

Coombs said she’s like to hear from harvesters on the topic