WISCASSET

Continuing a conservation project spanning 16 years, Wiscasset’s Shellfish Committee will soon be launching the town’s repaired soft-shell clam upweller in hopes of boosting future harvests.

The upweller, essentially a nursery where juvenile clams — or spat — grow until they reach a plantable size, was purchased from the town of Waldoboro 16 years ago. In dire need of repairs, it was taken out of the water two years ago, said Dick Forrest, a Shellfish Committee member.

This year the float was shortened by approximately 6 feet, the upper layer was replaced, and the town purchased 250,000 seed clams from Downeast Institute to grow in the upweller, said Forrest.

“A bridle is tied onto a mooring, and the water flows in here through a screen,” said Forrest on Monday, pointing to the head of the upweller which was ashore at the Old Ferry Landing after being repaired. The upweller will be towed to Chewonki Creek, where the clams grow well in the warmer, nutrient-rich water, said Forrest.

One of only two in the Mid-coast region, Wiscasset’s soft-shell clam upweller uses tides rather than a submersible pump to stream water through a system of 16 boxes with two layers of netting on the bottom, which are connected to a float. The clam spat rest on the netting at the bottom of the boxes and feed from the water continually flowing through.

“The flow is stopped by a piece of plywood, and instead of coming all the way through,” said Forrest, “it comes up naturally through the bed of clams and exits out a pipe.”

The clams will be divided evenly into four boxes initially, said Forrest, and as the clams grow and are sorted by size, they will be distributed throughout all 16 boxes in the upweller.

At the juvenile stage, 25,000 clams — approximately one-fifth of a centimeter in size each — can fit in two palms cupped together, said Forrest. In August or September, when they have grown to approximately 1 centimeter, the clams will be seeded in flats where they will grow until they reach a harvestable size.

The Shellfish Committee, which was allocated $10,000 in spending at Wiscasset’s annual Town Meeting, purchased the seed clams for $2,000.

“When they’re matured to the size that we would put them in the flats,” said Forrest, “they’d be worth $8,000- $10,000, so we’re saving a lot of money.”

The Shellfish Committee has also been spearheading a shell program to reduce acidification of the flats that Forrest said has shown remarkable results during its three-year span.

“We were in pretty bad shape a few years ago,” said Forrest, who decided to follow the lead of Mark Green, a professor at Saint Joseph’s College in Standish, who had conducted a study aimed at reducing ocean acidification by laying crushed shells, composed primarily of calcium carbonate, on flats.

“What was happening here was that the spat wasn’t setting and those that did set, the acid in the flats was dissolving the juvenile shells,” said Forrest. So after talking to the area biologist and Professor Brian Beal of the University of Maine in Machias, a leading expert in the field, Forrest started laying shells on the flats.

Purchased from an approved dealer that shucks clams for restaurants, Forrest said the shells cost $50 a ton, which came out of the Shellfish Commission budget.

“I did that for three years on my own — I put 17 tons of shells in the flats — and it’s really worked well,” he said.

Digging on a four-hour tide, Forrest said, a clammer in Wiscasset would typically be able to dig a bushel to a bushel and a half of clams.

“But you go some places like Harpswell and they’re getting three or four bushels digging in a tide,” he said. “That’s what we got this spring when we started digging, and the only thing that has changed is putting the shells in.”

While there have been green crabs in the area, Forrest noted that the numbers have been minimal compared to other areas and that he believes that acidification was to a greater degree responsible for poor clam sets in recent years.

“When you dig, if you find clams of just one size, you know you have a problem,” said Forrest. “There should be clams of different sizes, small juveniles, ones just under legal size and the legal size — that tells you that each year there has been a set.”

Since laying the crushed shells, natural sets have been more successful, Forest said, and now, as part of the conservation hours required to get a digging license, clam diggers have been continuing the effort and have laid several more tons of crushed shell this year.

Currently, Wiscasset licenses 12 Wiscasset residents and two non-residents to dig commercially, though all residents can apply for a recreational license and dig up to one peck of clams.