An upweller like the one Brunswick is purchasing for the Gurnet Strait. Courtesy of Hoopers Island Oyster Co.

A state grant will help Brunswick pay for an upweller nursery for quahog clams that town officials say is needed as the shellfish face threats from warming waters.

Town Manager John Eldridge last week notified the Town Council that the town’s application for the $15,000 grant through the Maine Outdoor Heritage Fund was approved.

The money will go towards the $19,000 upweller that the town is buying from Maryland-based Hoopers Island Oyster Co. The upweller is an 8-foot-by-20-foot dock-like structure with silos where baby quahogs are dropped when they are the size of a grain of sand. A pump distributes water through the silos, where the clams eat phytoplankton and grow faster while being protected from predators. When the quahogs reach about a half-inch in width, they are planted in the mudflats to finish growing.

Brunswick, the state’s biggest producer of quahogs, has about 1,600 acres of intertidal shellfish beds and licenses about 60 commercial shellfish harvesters, 15 student commercial harvesters and hundreds of recreational harvesters.

Dan Devereaux, the town’s coastal resources manager, said quahogs face threats from warming waters due to climate change. When the ocean absorbs more carbon dioxide, shellfish have a tougher time growing and their shells become thinner. Warmer waters also attract crabs that eat quahogs. In 2021, the town’s Coastal Resource Office noted a decline in baby quahogs, or spat.

Devereaux said he got the idea for an upweller from Cape Cod in Massachusetts, where many municipalities have upwellers to grow oysters.

“We’re hoping to take a page out of their book and be as successful,” he said.

The Brunswick upweller, which is currently being built, will be installed next summer in the Gurnet Strait off Gurnet Road near the Harpswell border. Devereaux said the first batch of spat, numbering about 350,000, will be planted in the upweller around June 2024 and taken out around October to be planted in the mudflats. The town also operates a floating quahog nursery at Mere Point that can grow up to 500,000 baby quahogs a season.

“We want to grow upward of a million a year,” he said, adding the town may explore buying a second upweller if next year’s batch is successful.

Jordan Shockley, CEO of Hoopers Island Oyster Co., said upwellers are becoming a more common form of aquaculture, which is the growing of marine life under controlled conditions.

“They’re really effective,” Shockley said. “They’re meant to be easy to use, easy to set up and as low maintenance as possible. … You’re going to maximize the growth and survivability (of quahogs).”

He said his company builds about 30 upwellers a year and ships them to coastal businesses across the country and internationally to Japan and Canada. He said in the last few years he has noticed coastal municipalities in the Northeast especially invest in aquaculture equipment like upwellers.