FREEPORT, Maine — A series of studies commissioned by the Freeport Town Council and conducted over the summer yielded new information about the invasive green crabs plaguing Maine’s coastal waters, but was largely compromised by timing and a lack of maintenance, according to a preliminary report.
Brian Beal, a professor of marine ecology at the University of Maine at Machias, reported on the studies earlier this month to the Town Council, which allocated $100,000 in 2012 for ongoing research of the crabs and their effects on the local soft-shell clam population in particular.
Clammers have speculated for several years that the crabs have decimated as much as two-thirds of their productive clam flats. A resource survey conducted in Spar Cove in June supported those claims, Beal said.
“The soft-shell clams resource is lacking or missing in the mid-to-lower intertidal area, and the only clams that are available are generally in the upper intertidal, where they don’t grow as fast and where habitat is more limiting,” Beal said. “Once that’s been fished out, there isn’t a lot of the resource to replace it.”
Two experiments conducted in Little River were designed to study the ability of nets and fences to protect clams from crabs. And while they showed that both methods can be used to deter crabs, they failed to provide more detailed insights.
That was partly because of timing. The experiments, designed to begin in late spring, required permits from the U.S. Army Corps of Engineers. When those took longer to acquire than anticipated, the start of the work was delayed until mid-July. By then, many of the clams were gone.
“Essentially, the nets got put out after the clams had already settled to the mud flats,” Beal said. “And so, before we put the nets on, the crabs had eaten them.”
It later became clear that predator-deterrent schemes need to be in place by late April or early May, Beal said.
Even if the timing had worked out, however, the Little River experiments would likely have been compromised. The study apparatus — which included six 30- by 30-foot areas for fencing and 10 22- by 14-foot areas for netting — were maintained for only the first few weeks of the four-month experiment, resulting in torn nets and pieces of fencing washed up on shore.
“The holes were as big to a green crab as walking into Wal-Mart,” Beal said.
The question of who was responsible for monitoring the experiments — and who was to supervise them — elicited frustration at the council’s Jan. 14 workshop. Beal maintained that local clammers and employees of Resource Access International, a Brunswick-based organization that has also contracted with Freeport to study the impact of green crabs, had said they would monitor the experiments. Beal said there was no money in the project budget to pay for people to regularly check the nets and fences.
A call to Resource Access International was not immediately returned.
Similarly, Beal conducted a green crab trapping study in the Harraseeket River from May to November that relied on clammers to record data, but most of the data sheets came back incomplete.
“It’s the tragedy of the commons,” Beal said. “Everyone’s responsible, so no one’s responsible.”
Beal will continue to perform green crab research in Freeport’s waters throughout the coming year using funds from an outside grant. He will conduct some of the same experiments again using stronger materials. This time he’ll see that the nets and fences are maintained by people getting paid to do it.
Green crabs aren’t new to Maine’s coastal waters, but in past decades their population was typically kept in check by frigid winters. However, rising water temperatures in recent years have swelled the crabs’ numbers.
Short of praying for more cold weather, Beal said, the best option for the town and clammers could be a municipal leasing arrangement, in which individual clammers could lease from the town a flat of intertidal area — say, an acre or two. In an area that small, fencing, netting and trapping could be properly maintained, while potentially eliminating the green crab threat. The municipal flats could serve as a crucial supplement to traditional clamming and help the industry survive.
“It’s their garden,” Beal said. “Whatever the individual can do in their flat belongs to them. It’s up to them to make it work.
“You can’t net the world. It’s not possible. But you can net small places, and that will work. What you’re doing is creating pockets of clams so people don’t have to go hunting for them. They know they’re there. It’s the difference between hunting and gathering, and a farmer mentality.”