June to October in Massachusetts is the growing season for some of our most popular shellfish, including quahogs and oysters. To keep the harvest sustainable, town shellfish programs are raising millions of them each year, in tucked-away places that are easy to miss.
At Stage Harbor in Chatham, the harbormaster’s building looks ready for a scenic photo. But don’t miss the action inside.
The first floor is devoted to the upweller, a system of shellfish tanks connected by a constant flow of water.
Rachel Hutchinson walks between the rows of open tanks. As the town’s shellfish propagation specialist, she knows all the details about the upright plastic tubes inside. They’re called silos, each about 18 inches across, with screen-like mesh at the bottom.
“The purpose of this facility is to get as much food past our baby animals as possible,” she says.
Raw seawater, straight from the harbor, is pumped in at a rate of 800 gallons a minute.
“The growth in here’s much faster than growth out in the environment, because they just have that opportunity to do nothing but feed,” she says.
Chatham shellfish staff oversee the annual rearing of close to 3 million quahogs and 2 million oysters. The quahogs arrive looking like grains of sand, a millimeter across.
As they grow, they’re separated by size to give the smaller ones a fair shot at competing for food. And they’re spread out, into more silos.
Hutchinson says the upweller keeps the tiny shellfish safe from predators — like crabs, ducks, and moon snails.
“A lot of the snails will get them, drill a hole through their shell and suck out any of the body,” she says. “So we try and get them to a point where their shells are a little bit thicker.”
When they’re big enough, they’re moved into the natural environment. They’ll still be protected at first — the quahogs under nets, and the oysters in floating cages.
Eventually, shellfish staff broadcast them from a boat into the wild.
Hutchinson says every town on Cape Cod has a municipal shellfish program. But they don’t all do it the same way.
Some have floating upwellers outdoors; that’s something Chatham hopes to add.
Barnstable has a floating upweller on the north side of town for planting in Barnstable Harbor, and one on the south side for North Bay, Cotuit Bay, and West Bay.
The town also sends some of its adult quahogs to a hatchery in Maine.
“They spawn them there, and then they give us seed back from our own brood stock,” says Amy Croteau, the Barnstable shellfish constable. “It's just a way of sort of diversifying your crops.”
It takes about 18 months to grow oysters from seed to harvest size, and three years for quahogs.
Croteau says Barnstable raises shellfish not just because the state requires it of coastal communities, but also because the town has a booming fishery and wants to keep it that way.
Now, let’s head over the bridge to Onset Beach, where a new shellfish program by the nonprofit Buzzards Bay Coalition is in its first season.
“So this looks like a sort of generic raft, but you can feel the water pump running below us,” says Katherine Garofoli, director of the coalition’s Onset Bay Center.
Just off the town pier, she opens hinged panels in the raft to reveal shellfish silos underneath. Here, the silos are square. They have a mesh bottom, and the water is drawn up from below through tubes.
With help from Woods Hole Sea Grant and Massachusetts Maritime Academy, her organization was able to get a variety of sizes of oysters. They’re also raising scallops, with 4,000 scallop seed purchased by the town of Wareham.
“Oh, my gosh, I can't believe how big the scallops have gotten,” she exclaims. “I'm sorry, I'm like — these are my babies. Like, I love them.”
The scallops arrived at about four millimeters wide and quadrupled in size in three weeks.
Education is a big part of the plan for the Buzzards Bay Coalition upweller. Two Mass Maritime cadets are working with Garofoli, and the coalition hosts learn-to-shellfish programs.
“People will be able to go out in the fall and start to harvest their scallops,” she says. “And hopefully we have an opportunity to teach them how to do it the right way, and get the permits they need, and the equipment they need, and to do it safely.”
Back in Chatham, Shellfish Constable Renee Gagne says propagation is about more than supplying the harvest; it makes shellfishing sustainable for the long term.
And, there’s this:
“It's fun to do. It's really a fun activity for people to bring their kids and their grandkids out to our local waters … and bring harvest home and eat it,” she says. “I mean, what's better than that?”