Shellfish Commission seeks ways to improve clamming

Thu, 11/26/2020 - 6:15pm

Each spring, the New Shoreham Shellfish Commission reseeds the Great Salt Pond with some 35,000 quahogs of harvestable size to supplement the native clams so that both resident and visiting clammers can have a satisfactory experience. In the past, former members of the commission have likened this practice to holding an Easter egg hunt and they set a goal to make the GSP more sustainable.

One idea the commission has come up with is to move clams from deeper-water areas to shallower ones, especially from an area where the quahogs appear to have damage, or degradation, to their shells, either from acidic conditions or lack of aeration.

Vice-chair George Davis has taken the lead in contacting the R.I. Department of Environmental Management and the R.I. Coastal Resources Management Council to explore the possibility of performing the transplant, and on Tuesday, Nov. 17, he updated his fellow commission members on his research so far.

The agencies had some questions. Davis said the DEM asked if there was a map of the proposed source of the clams, and of their proposed destination. They also questioned whether there would be a disturbance to a resource or spawning sanctuary, although Davis said he’s “not sure that’s a problem.” The DEM also asked if the biomass or density of clams in the area was known, and what other benthic species might be in the area.

Based on his research, Davis said he had found references to “dredge surveys” performed from at least 1983 through 2000 in the book “The Ecology of Block Island,” put out by the Rhode Island Natural History Survey in 2002. 

The original surveys were never digitalized and are probably hiding in a file cabinet somewhere, but Davis has the DEM on the hunt. Meanwhile, despite confusion over the term dredge survey, versus what was more likely “spot surveys” the need for new surveys to be performed by the DEM was something all attending the Zoom meeting could agree on.

The Shellfish Commission also agreed on designing and performing their own surveys with help from those experienced to teach them how to do it. This time the aim was to determine the state of soft-shell clams. The discussion was prompted by correspondence sent in by Chris Warfel, which involved soft shell restoration efforts in other parts of New England.

In the past the Shellfish Commission has attempted to reseed them, although they thought their efforts were largely unsuccessful and abandoned the practice. Invasive green crabs are believed to be one of the soft-shelled clams’ chief predators, as are people illegally taking them from the pond. (The harvesting of soft-shell clams in the Great Salt Pond has been prohibited for several years.)

“My opinion is we should develop a base-line” estimate of the soft-shell population, said Davis. “I’m biased toward citizen science, and I’m biased by data.”

“There is a population out there,” said Harbormaster Kate McConville, adding that this year the shellfish wardens found people digging them and that she would like to know more about how many there were. “It needs to be surveyed.”

Chair Wendell Corey said he had “experience digging soft-shells 20 to 30 years ago,” and suggested simply blocking off areas to study. “I would love to see them come back.”

“Pick some sites,” said McConville. “Now’s the time to do it. And I’m pretty sure we have someone on the commission who’s good at mapping: Mr. [Jon] Berry.”

When Davis made a motion to design a survey for soft-shell clams, McConville asked for it to be modified to include all species present at the selected sites.

“It makes sense,” said Davis.

“Whatever you said Kate, that’s what I want to do,” said Commissioner Jon Berry.

Reducing the invasive green crabs

Understanding and attacking the green crab population has been one of the aims of the commission over the past two years. The first step was gaining an understanding of their biology, and Davis started more formally researching the local population this past spring. Unfortunately, because of Covid-19, his research was delayed until late May, and the window for determining just when the crabs molt and reproduce appeared to have closed.

Davis has found that there is a robust market for live green crabs that can be used for bait, and he reported that commercial fisherman Joe Fallon, a former member and chair of the Shellfish Commission, had set out traps and removed approximately 3,000 of them from the pond.

McConville asked for more detailed information, including Fallon’s timeframe.

Davis said he didn’t know the details, but he thought Fallon had mentioned 43 traps set out in the pond. “It was just a parking lot conversation,” he said.

“I think it’s a good effort, but probably not touching the amounts in pond,” said McConville.

“We’re never going to get rid of them,” said Berry, adding that you could knock down the population. “You have to hit it hard and fast’ and then maintain it.”

“You need to figure out when they’re molting and get the females,” said McConville.

“It wasn’t that long ago that we didn’t know there was a market” for the green crabs, said Davis. “It’s nice to know.”

“It’s useful,” said McConville, but she was wary. Neither the state nor the town regulates the taking of crabs. “I need to know who is coming into the pond,” she said. “I’m not having thousands of traps in the Great Salt Pond.”

“I think what Kate hit on is, it’s got to be controlled,” said Corey. “We have to know who’s doing it, and where and how.”