A truck heads off Deer Isle along the island's recently repaved causeway in August 2022. The Maine Department of Transportation has started an evaluation of the causeway, which locals are increasingly worried will fall prey to rising seal levels. Credit: Ethan Genter / BDN

When almost 100 people tuned into a meeting about the future of the Deer Isle causeway last week, just about everyone was of the same mind: the only stretch of road on or off the island needs to be strengthened to deal with climate change.

And while most people raised the potential public safety threats and economic devastation that a washout of the causeway could pose, one man raised a different topic: baby scallops.

Marsden Brewer, a Stonington commercial fisherman and scallop farmer, encouraged state transportation officials to consider restoring the water flow the causeway blocked off when it was built in the late 1920s as the Maine Department of Transportation undertakes an evaluation of the road to see what can be done to protect it. Such a restoration could potentially bring more baby scallops and other species to the western side of the island, possibly bolstering Deer Isle’s fishing-dependent economy.

“It’s important while we’ve got this opportunity to take advantage of it,” Brewer said. “It’s only going to come along once in a lifetime.”

The causeway, a little less than a mile stretch of asphalt, was built in 1927 atop of a sandbar to make it easier to get on and off Deer Isle. What was once only passable at low or half tide, now can be driven across any time.

Officials worry that rising sea levels could make the stretch of road, one of the most at-risk infrastructure in Hancock County, increasingly susceptible to a washout. It’s become normal for extreme high tides and storm surges to wash over the causeway, sometimes blocking the road with rocks and seaweed. Municipal leaders wonder if it should be raised or turned into a bridge.

Brewer, one of the pioneers in the Maine  farmed scallop movement, is leaning towards the latter. Before there was a causeway, it was a singular tidal flat where water passed through. The eastern Maine current, a water flow that Brewer called the “larval superhighway,” would deliver baby scallops and other species from Down East and the Bay of Fundy.

Stonington lobsterman Marsden and Dana Morse of the University of Maine Marine Extension Team check the test cages used to grow scallops near Crotch Island off Stonington. Credit: Gabor Degre / BDN

Pre-causeway, Little Deer Isle had a thriving scallop fleet that was “destined to become the most important fishery of the kind in the state,” according to the United States Fish Commission 1889 report. In the late 1800s, there was a fleet of about 26 scallop boats off Little Deer Isle that caught about a quarter of Maine’s total scallop catch. 

That’s pretty much disappeared in the 133 years since.  

“There’s been a lot of scallops there over the years,” Brewer said. “It had been a productive area for a long, long time. But it’s kind of died out.”

Now little water from the eastern current makes it through the causeway to the western side.

Though there are some culverts nearby, none are built into the causeway, said Dale Doughty, the director of Maine DOT’s planning bureau. Only the water that permeates through the causeway, splashes over in storms or works its way around the island makes it into the opposite cove.

Doughty, who spoke at the islandwide causeway meeting last week, said ecological impacts will be considered both during the ongoing evaluation and in any potential future permitting.

Anything that DOT builds new does try to get back to original environmental conditions.

“A lot of culverts these days, we are replacing [them] with bridges,” Doughty said.

The replacement of the Machias Dike with a bridge has gone through similar talks. That project is being looked at partially to improve water flow, ecological restoration and salmon passage, but has also drawn concerns from landowners who worry their properties could see larger tidal fluctuations.

That concern hasn’t been raised by anyone in Deer Isle, though the evaluation process only just started.

Some officials noted that the combination of ecological restoration, public safety and economic importance to the island could help get the causeway to the top of funding lists.

Brian Beal, a marine ecology professor who has done work on the clam flats next to the causeway, didn’t know what reopening the water flow in the cove could do for local fisheries, but warned against getting hopes too high. Water conditions, predators, and other factors are vastly different from what they were when Little Deer Isle was a scallop powerhouse in the late 1800s.

Still, it’s nice to see people thinking ecologically so early in the process, he said.

“I think it’s a great conversation to have now,” Beal said.