Shellfish Upwelling System Planned For Mill Pond

By: Tim Wood

Aquaculture Research Corp. will open a new shellfish upwelling facility in Chatham's Old Village. FILE PHOTO

CHATHAM – For 30 years, the Dennis-based Aquaculture Research Corporation maintained a satellite shellfish upweller on the shores of Stage Harbor. The facility allowed the company, which annually sells millions of seed shellfish to Chatham and other Cape communities, to take advantage of the warmer Nantucket Sound waters to grow out shellfish earlier in the season than it could at its Cape Cod Bay-side facility.

More than two years ago, the company, known as ARC, lost its lease on the building at the corner of Champlain and Stage Harbor roads where its upweller was located. Owner Stage Harbor Yacht Club needed the space for its summer programs.

After an exhaustive search covering the Nantucket Sound shoreline from Bourne to Chatham, ARC is planning a new upwelling system on Mill Pond, adjacent to First Light Boatworks off Eliphamets Lane in the Old Village.

“The property owner and the tenant, First Light Boatworks, have been very accommodating to us,” said ARC President and CEO Rob Doane. “They really want to see this happen.”

Nantucket Sound waters warm up as much as a month earlier than Cape Cod Bay, and warmer water means more naturally occurring algae to feed the tiny shellfish. ARC's facility in Dennis grows quahogs out to one millimeter fed with algae it produced on its own, but once the shellfish reach that size they eat so much the company can't keep up, so it needs to use water with naturally occurring algae. That's where the Chatham upweller comes in. Growing out the shellfish there allows ARC to provide its customers will larger seed in the spring.

Having ARC nearby has always been beneficial, said Shellfish Constable Renee Gagne. The town buys more than two million seed shellfish from the company annually through the shellfish revolving fund, and last year bought another 300,000 seed quahogs with funding from the state Division of Marine Fisheries. The seed is grown out in the town's own upwelling system located Old Mill Boatyard. Having the ARC facility right next door provided easy access to seed as well as someone to bounce questions off of, she said.

“We just walked over and picked up our seed,” she said. “Hopefully that relationship will return.”

Doane agreed, noting that it's an “ideal situation” for Chatham shellfish to come from an upweller right here in town. “The clams are grown right here and they're going right back in,” he said.

The shellfish – primarily quahogs and oysters, although surf clams and scallops could also be raised, depending upon how each responds – will be grown in four two-foot-deep tanks, each 15 feet long and five feet wide, located behind the First Light boat-building barn. Four five-horsepower submersible pumps suspended from the nearby pier will pump water into the tanks from Mill Pond, at a flow rate of 500 gallons per minute. An 18-inch corrugated outfall pipe will discharge the water back into Mill Pond.

Exactly how many shellfish the upweller will be able to grow out won't be known until the facility has been operating for a season, Doane said. The primarily purpose of the Mill Pond system is to fatten up shellfish to meet the spring sales demands. The upweller will operate from April to January, when pumps and equipment will be removed and serviced; should temperatures plunge before then, the equipment will be removed early, Doane said.

On Wednesday the conservation commission was set to vote on whether ARC needs to file a notice of intent for the project.

The ARC facility is separate from a new upweller the town is proposing along Bridge Street. The town's shellfish propagation program has outgrown the existing upweller, which is old and badly in need of repairs. A plan for a larger upweller on Bridge Street was recently sent back for design revisions by selectmen. Chatham's upweller is larger than ARC's planned system and grows shellfish out to a larger size, Gagne said.

She'll be giving an “upweller 101” presentation to the board of selectmen on Feb. 5 to educate the board and the public on exactly what a shellfish upwelling system does.