A Hard Day’s Clam

Settling in to their new home

Although shifts in predator populations are beyond the Conservancy’s control, the project has tweaked aspects like the size and origin of their relocation stock. Regular counts and large-scale surveys over the past four years have allowed the project’s scientists to identify how to achieve the highest survival rate. So far, under the best conditions, more than 80 percent of the stocked, large adult clams, called chowders, are still alive.

The surveys settled a debate over whether to stock larger, market-size mollusks instead of small clams that would need less food and have more of their 30-year life span ahead of them. As it turned out, any clam less than about an inch (25 millimeters) was too vulnerable to predators. “Bigger is better,” says Mike Doall, a research scientist at Stony Brook University who will assess the health of the few quahogs that Clapp manages to rake up.

Factors other than size, such as the clams’ origins, also seem to be important, though the reasons are less clear. Together, Doall and Clapp speculate that the reason for the low harvest at one of the sites is probably that the acre-wide patch had been stocked with hard clams from Oyster Bay off Long Island’s North Shore. For mysterious reasons, these clams are “just like a magnet for predators,” says Doall.

In contrast, stock from Greenwich Cove in Connecticut survives, and spawns with a vengeance. Doall generally gives this pedigree high marks for reproductivity because of the appearance of their gonads: large and ripe.

The Conservancy buys its bushels of Connecticut clams from Ocean Rich Distributors in Brookhaven. According to Derek Schleede, the company’s owner, these transplants are “the new kid on the block [who] wants to hang out with everyone. Next thing you know, there are babies everywhere,” Schleede says, as he bounces across his cluttered office to point to a map of the fruitful sea land he leases in Connecticut.

It’s still an open question if, in addition to spawning, the new clams in Great South Bay are improving aspects of the bay’s ecosystem, such as water clarity. Doall does have some indications that the population of invertebrates — worms, arthropods and crustaceans — inside the clam patches has climbed, a sign that the bay bottom is getting livelier. Although he has not yet confirmed these findings, Doall believes that hard clams are stimulating biodiversity by adding nutrients to the sediments lining the bay’s bottom. “And when they die, they leave these shells behind that critters can live in,” he says.

Hard decisions

The Conservancy is stocking more chowders this June but, if the team continues to see a rise in the bay’s hard clam population, they will start reducing the number of transplant clams and money it puts into the project. The $3 million that the agency has spent so far on the project has come from many supporters, including Long Island’s Suffolk County, the National Oceanic and Atmospheric Administration Restoration Center, the Knapp-Swezey Foundation, Inc., the Wildlife Forever Fund and several private organizations.

Since the Conservancy’s efforts have become a rallying point uniting town governments and independent baymen under the common hope of recovering the bay’s ecology and economy, the Conservancy’s Clapp says the group may decide to continue overseeing the management of the underwater lands. The organization originally intended to hand over the restored bay land to Babylon, Islip and Brookhaven.

Town governments are already showing signs of adopting policies to establish more sanctuaries on their portions of the bay bottom outside of the Conservancy’s lands, and enforce them as “no fishing” zones. Part of the reason the towns’ stocking efforts have not been rewarded is that they have to mark any off-limit spawning areas with buoys that end up being advertisements to shellfish thieves.

Another decision the Conservancy would have to make is whether or not to open some of its lands to clamming, this time with harvest restrictions in place. Tom Carrano, the assistant waterways supervisor for the town of Brookhaven, who clammed during the bountiful summers of the 1970s, says that the bay cannot go back to a time when it sustained 700 clammers. The timing might be right for restrictions because fishermen now have little interest in the virtually barren bay bottom, he says.

But interest is already trickling back into the bay, according to Bill Hamilton, the vice president of the Brookhaven Baymen’s Association, which has about 50 percent of the town’s baymen as members. “We have quite a few guys that for the last 10, 15 years have been carpenters or did something else and now, because of the economy, what we have going on, they want to come back possibly and dig clams,” he says. Most of the current commercial baymen, who stand to earn about $70 for each large, potato sack-sized bushel of clams, favor restrictions on the number of new shellfishing licenses. Another layer of protection that Hamilton supports is to open parts of the Conservancy lands only on the condition that the clam density in that area does not become too low.

Even if the land remains closed, it could still benefit fishermen in surrounding areas. The Conservancy’s abundant clam population could produce enough larvae that some of them drift in currents created by wind into neighboring town waters, like Brookhaven’s, settle there and grow into adults.

All the talk about what to do with the land hinges on the ability of the Conservancy to actually resurrect the clam population. Clapp points out that the bay needs another two good consecutive years of clam survival and reproduction like it saw in 2006 and 2007. Monitoring how well the population rebounds in 2009, after the bout of brown tide it had again in 2008, will tell the marine scientists and fisherman a lot about the future of the Great South Bay.