FREEPORT – Researchers studying the green crab population along Freeport’s clam flats have trapped far fewer adults of the species this summer than last, but they’re not sure why.

Brian Beal, a professor of marine ecology at the University of Maine at Machias, is spending his second year leading a study of green crabs along the shores of the Harraseeket River. The crabs are predators of soft-shell clams up and down the Maine coast, and Beal’s team is looking for ways to control the crabs. The town of Freeport commissioned a $100,000 study last year. Beal returned to Freeport this year and will be back again in 2015, thanks to a $200,000 state grant.

Chad Coffin, president of the Maine Clammers Association, and other local clammers, have been trapping green crabs in the upper reaches of the Harraseeket since spring, and have found an average of 59 crabs per trap – compared to 12 last year – because most of them are juveniles. Some people have speculated that the cold winter of 2014 killed many of the adult crabs, but Beal and Coffin aren’t buying it.

“We’re not sure if that’s a reasonable assertion,” Beal said last week. “If there were a large amount of winter kill, there would have been reports from somewhere along the Maine coast of thousands of dead crabs. We should have heard across the state from people, and we didn’t.”

Coffin said he has seen a minimal improvement in what has been a dismal scenario for local clammers.

“There are more juvenile clams that have survived in the upper reaches of the estuaries and bays,” Coffin said. “A clam digger has to be an optimist. That makes people tend to exaggerate observations sometimes. We’re still not seeing any significant rebound. You see slight rebounds here and there.”

So, where did all the adult green crabs go?

“They could be in the deeper water because of the cold,” Beal said. “Am I confident of that guess? I’m not.”

He speculated that perhaps the larger crabs have moved on, having eaten many of the clams in the Freeport area.

“They might have gone on to greener pastures,” Beal said, “but not everyone is doing studies, so we don’t know.”

Meanwhile, there are hordes of young green crabs around.

“My concern is that if we have a mild winter, we know that there are an awful lot of small crabs out there,” Beal said.

“There’s still a gazillion crabs running out there eating everything up,” Coffin said.

Coffin, fellow clammer Clint Goodenow and others have been trapping crabs, sizing and sexing them since spring, and will continue until sometime in November.

“We’re still going strong,” Coffin said. “Contrary to popular report, we may be catching more crabs than last year, just smaller ones. It’s a reality check for people who think they’ve diminished. That tells us that the large crabs have either had severe mortality associated with the winter, or that they have moved on to where there’s more food.”

In an effort to boost the population of young clams, Beal’s crew has experimented with a new method of raising them this year. They placed 50,000 baby clams in barrels, or upwellers, in the mouth of the river, hoping they will survive into next year, when they could be harvested. The clams will be protected from predators and eat the plankton in the seawater. As hoped, they have grown.

“They have grown tremendously,” Coffin said. “We learned there is a time period when water temperature at the surface provides tremendous growth. The plan was to over-winter them in cages, submerged. But with the early growth, I think we’re going to maybe plant them instead of over-wintering them.”

Coffin said that the researchers have been out on the flats regardless of conditions.

“We haven’t missed a day in 35 weeks,” he said. “The data is going to be extremely valuable data. We’re looking for size, depth and distribution of green crabs in the Harraseeket.”