HARPSWELL — A University of Maine researcher studying the decline of soft-shell clams in Casco Bay has found an effective way to protect clam populations, but is struggling to capture the attention of diggers.
Brian Beal, a professor of marine ecology at the University of Maine at Machias, is going from town to town along Casco Bay presenting research, insights and strategies into the ways that clammers can protect and restore soft-shell clam populations.
Beal’s latest findings – collected from field experiments in Freeport’s Harraseeket Bay – suggest that predation is the defining cause of decline among soft-shell clam populations.
He called it a “double-pronged” problem: invasive Japanese green crabs crush the clams’ shells, and milky ribbon worms, which live in the mud, attack the clams from below.
His findings also disprove the reasoning behind the municipal enforcement of conservation closures, where towns close off clam flats in the hope that time will replenish clam populations.
Beal called the action “akin to doing nothing” or “praying to the zooplankton gods.”
Because clam flats are managed by individual municipalities, Beal said there isn’t a good mechanism for communication between towns. By scheduling the speaking circuit, he hopes to provide an opportunity to share solutions to a common problem.
Beal’s research is not affiliated with or funded by the towns; his work is supported by grant funding he acquired through the Downeast Institute. And so far, his talks have not been well attended by the audience he wants to reach.
While Brunswick, Harpswell and other towns in the same intertidal zone have struggled to cope with the declining population of clams in the last six years, Beal said he didn’t see clammers from either town at his talk Aug. 18 in Brunswick’s Curtis Memorial Library.
The poor attendance may be the result of what Maine Clammer’s Association President Chad Coffin – who helped Beal and his team gather samples from Harraseeket Bay last week – calls “management’s inability to wrap their brains around how straightforward” Beal’s findings are.
Put another way, Coffin said clammers and municipal management committees are reluctant to adapt to the changing marine ecosystem. According to Coffin, either they are in a state of denial over the immensity of global climate change, or simply set in their ways, which have built up over a long tradition of clamming in Casco Bay.
For example, Beal corroborated Coffin’s finding that there are still enough clams surviving in the upper-tidal areas of the bay (where there is less water coverage, and thus fewer predatory green crabs) to allow clammers to continue harvesting without protection against predators, and still get their money’s worth.
This not only creates a false sense of security, but also reduces the number of upper-tidal clams that Beal calls “remnant spawning stock.”
“I’m a little worried of what’s down the road” if there comes a day when even the upper-tidal clams disappear, Beal said.
“It’s a crustacean’s world,” Coffin said.
Beal hopes stubbornness won’t be the cause if the clams disappear. With exasperation, he recalled in an interview Tuesday a time when a clammer told him, “I’m sick of science,” and pounded his fist against a table.
“(Science) disrupts their paradigm,” Beal said with a mix of sympathy and frustration.
However, this less-than-ideal reception hasn’t stopped Beal from trying to get the word out on what’s he’s learned, especially given that his research this summer has developed an effective new method for combating predators.
In the past two years, Beal has experimented with various barriers to block crabs, such as nets and boxes, and his most recent research suggests that wooden and mesh boxes might be the key to protecting clams until they reach a marketable size (which, in Maine, is 2 inches wide).
The boxes, which have wooden sides to protect against crabs and mesh floors and ceilings to keep worms out, are staked in the mud in the early spring. Clams then seed themselves within the protective walls and grow in safe refuge from predators.
Beal has removed boxes from otherwise barren mud flats that “contained upwards of 6,000 clams,” showing that factors such as rising sea temperatures and ocean acidification do not directly affect the clams by dissolving them or killing them prematurely.
If Beal sounds exasperated, it’s because he is. But he still hopes that clammers and municipalities will embrace the science that might be the key to reducing juvenile clam mortality rates.
“The reason I’m doing this is so clammers can make a better living” and to empower them to make decisions “based on fact, not fiction.”
David Wilson, a member of Harpswell’s Marine Resources Committee, said he didn’t go to Beal’s talk last week because he was out digging clams.
He is aware of Beal’s research, but it isn’t the focus of the committee’s review. “Not everything works for every town,” Wilson said. He also questioned the logistics of locating the boxes on the flats, which will require a lot of effort on the part of clammers.
Harpswell will continue to fight the problem by trial and error, he said, and, as it happens, some of those efforts have resembled what Beal is doing, such as implementing nets and covered barrels to combat green crabs.
But Wilson says that he hasn’t found an effective way to fight the milky ribbon worms.
Of the conservation closures in Harpswell, however, Wilson did echo Beal’s frustration. He says the closures in Harpswell constitute “acres and acres of flats,” which”I personally knew wasn’t gonna make a difference.”
In comparison to Beal, he sounded more resigned than frustrated.
“If our water continues to warm,” Wilson continued, “there’s not much we can do.”
This is the first summer since 2012 that Wilson has harvested clams; it’s the first time there have been enough to make it worth his time.
When asked if he’d be able to adapt to the changing marine environment, Wilson said he didn’t know, but he’s trying. If the clams go away, he said, he’ll work construction.
Brian Beal shows off the growth of clams he seeded and harvested in Freeport’s Harraseeket Bay. The dark, naturally occurring disruption link on the clam shells tell Beal how much growth occurred since he planted them in April.
Sara Randall, a colleague of Brian Beal, explains how wooden and mesh boxes help protect clams from predators like milky ribbon worms and green crabs.
Brian Beal said the milky ribbon worm comes up from the mud of Casco Bay to attack soft-shell clams.