Moriches Bay scallops may offer hope for a restoration in the Peconic

The seeds of a possible restoration for Long Island’s cherished Peconic Bay scallops are being cultivated in tanks in a hatchery in Southold, the offspring of shellfish from nearby Moriches Bay.

At the Cornell Cooperative Extension shellfish hatchery at Cedar Beach in Southold, marine biologists this year launched a novel approach to restoring Peconic Bay scallops after four straight years of die-offs. The plan: Spawn scallops from Moriches Bay, which appear to be thriving,  and introduce their offspring into the impacted Peconic scallop population.

The scallops are of the same species, but researchers hope the Moriches Bay scallops have a genetic advantage to help them thrive in the face of warming waters and a deadly pathogen that could be impacting the Peconic Bay scallops. They hope that those scallops can bring any genetic advantage to the waters of the Peconic.

Part of the plan includes spawning the Moriches Bay scallops in the fall/winter period rather than their natural spring spawn, giving the scallops a chance to grow larger before being seeded in the wild without potential infection by a pathogen that Stony Brook University scientists discovered has contributed to the massive die-offs.

“We’re getting a jump-start from what’s occurring out in Mother Nature,” said hatchery manager Mike Patricio, who tends to the tanks of scallops — the size of grains of sand — seven days a week. The objective is to “grow the biggest-size seed as possible so that when we plant them they have a better chance of surviving in the wild.”

Work on this part of the program began last month, when the fittest of 300 Moriches Bay scallops were used to produce more than 2 million fertilized eggs. In the weeks since, more than 1 million have metamorphosed into scallops, said Harrison Tobi, aquaculture and shellfish specialist for the Cornell Cooperative Extension, which is partly funded by Suffolk County.

Tobi and his colleagues decided to spawn the Moriches Bay scallops after finding they had a “really robust population” compared with the Peconic Bay scallops. “Landings in Moriches Bay are much higher than we saw in the Peconic,” he said.

“We are using that information under the assumption that those Moriches scallops might possess a genotype of tolerance to this parasite,” Tobi said, adding:

“Our hope is that by spawning Moriches Bay scallops and using them in our planting efforts, that they can take those genetics or that genotype and pass it off to their offspring when they spawn after we plant them. Basically, we’d just be speeding up evolution. We are not changing species. It’s just taking a potential genetic trait for tolerance and helping facilitate that at a larger scale in the Peconic.”

Most scallops live no more than two years and complete their spawn in the wild by late spring or early summer. Biologists worry a trifecta of impacts — the pathogen, warming waters and the stress of mating — combined to increase mortality to upward of 98% in some areas monitored by Cornell over the past four years, though those rates may have moderated to just under 90% last year. The scallop-harvesting season runs from the first Monday in November through the end of March.

Since 2005, the Cornell hatchery has had a scallop spawning program that has helped augment wild scallops in the Peconic. It helped push scallop landings to record highs until the fall of 2019, when the first die-off occurred. Die-offs have happened every year since, cutting the landing value of the bay scallops to less than $200,000 a year from the 2018 high of $1.5 million, Tobi said.

From their tanks at the hatchery, where the scallops are fed precise levels and types of the algae that is their sole food, the scallops will grow to around the size of dimes before being moved out to secondary hatchery facilities.

Cornell will continue nurturing them in the lab for another month or two, “then we’ll slowly bring the temperature down and move them out into aquaculture here at our site,” Tobi said, noting that once the scallops reach a 1 millimeter shell, the survival rate increases sharply. Next, the scallops will be moved to a spawner sanctuary in Orient Harbor, where they will be monitored and further grown, some for up to two years, before being seeded in seven to 10 spawning beds across the Peconic.

Up to 200,000 scallops could be planted in the Peconic this year, Tobi said, meaning they will mix with existing scallops in the hope of sharing whatever advantages they bring to the wild population.

“They will be the parental generation for the robust population spawning in the spring of 2025,” he said. 

Getting scallops to spawn in the lab is a precise science. In early January, Patricio and hatchery technician  Kate Rossi-Snook  were able to simulate the conditions for spawning by raising the temperature of the Moriches Bay scallops in tanks to that of spring-spawning waters, leading the hermaphroditic scallops to produce eggs and sperm.

Research has shown that fall-spawn scallops are more resistant to a pathogen that has plagued the scallops for the past four years, which could make them more able to survive when these young scallops are transitioned to other waters of the bay later this year.

It’s not the first time the hatchery has used scallops from outside the Peconic in its efforts to bolster the local population. Last year, Cornell used scallops of the same species from Martha’s Vineyard, Massachusetts, to test survival rates, and found they fared better than their Peconic Bay cousins in the same waters, Tobi said. This year, the spawner sanctuary in Orient Harbor is also testing scallops from Cape Cod. Neither will be seeded into the wild, but will be used for another year of survival studies.

Cornell has yet to collect specific data on genetics of the Moriches Bay scallops to fully understand why they appear to be thriving, but expects to get results of tests in coming months. “Did they survive because of genetics or maybe because the pathogen is not as intense” in Moriches Bay? Tobi said. “We don’t entirely know why that population was so healthy this year.”

All the work is aimed at restoring a fishery that has been an essential winter revenue source for North and South shore fishing communities for centuries.

“The goal is to bring back the fishery, to restore the fishery,” Tobi said, “because a lot of people’s livelihoods depended on this, and we’re seeing over a $1 million reduction in dockside value, and it’s a pretty small community of baymen out here.”

He estimated that if successful, the Moriches Bay seeding program could show results in two to five years. “If they have a higher survival rate in the wild and slowly repopulate the bay, that could take a couple of years before we could see a significant increase in landings,” he said.

By Mark Harrington

mark.harrington@newsday.comMHarringtonNews

Mark Harrington, a Newsday reporter since 1999, covers energy, wineries, Indian affairs and fisheries.