Why Did The Scallops Die?

Pictured Above: A quiet sunrise on Opening Day at the New Suffolk boat ramp, which is usually clogged with baymen setting off to seek out the first scallops of the season.

After two banner years for the Peconic Bay scallop population, this year’s season, which opened on Nov. 4, has turned out to be a dud. A possible culprit? Climate change.

Marine scientists on the East End have long been circumspect on the role of the warming planet in our local ecosystems, but this year, after a big scallop die-off when high water temperatures coincided with their first spawning in June, LIU Post Biology Professor Dr. Stephen Tettelbach is not mincing words.

“I firmly believe this is driven by climate change,” said Dr. Tettelbach, who has been involved for decades in the efforts to revive the Peconic Bay scallop, in an interview with The Beacon just after the start of this year’s scallop season. “Going forward, we have this specter hanging over us.”

Baymen and scientists who’ve been combing the Peconic Bay system throughout the summer had a dire prediction heading into opening week of scallop season: Most of the adult scallops had died. Scallops live just two short years, and they can’t be harvested until they have a growth ring on their shells that indicates it is their second year of growth.

Many baymen didn’t even bother to go out for scallops on opening day, and by the second day of the season, the bays were eerily bereft of the usual swarm of skiffs pulling dredges.

“The die-off in most areas was 95 to 100 percent, most severely in Flanders Bay and Great Peconic Bay,” said Dr. Tettelbach, whose team has monitored 20 sites throughout the Peconic system for 15 years. They had added an additional 15 sites this year in an attempt to learn more about the die-off. “We saw a marked 80 to 90-plus percent death in Southold Bay, Orient and Northwest Harbor. It’s bay-wide.”

Dr. Tettelbach said the June die-off coincided with the scallops’ first spawn of the year — which is a great stressor on these small shellfish — and also coincided with a time that high water temperatures and low dissolved oxygen levels occurred in the bays.

Relying on U.S. Geological Survey measuring devices at the Route 105 bridge across the Peconic River between Aquebogue and Flanders and in Hallocks Bay in Orient, Dr. Tettelbach said water temperatures during the spawn were 81 to 82 degrees in Orient and 84 to 85 degrees at the Route 105 bridge — close to the lethal limit for scallops, even when they aren’t spawning.

“Spawning is a stressful event for adults,” he said. “If it overlaps to any degree with high water temperatures, it can cause mortality.”

The good news, he said, is that, even if the heat killed the adults, some of the spawning was successful, and the bays are filled with a decent number of tiny scallops, known as “bugs,” which can become next season’s harvestable scallops.

“There are a lot of bugs out there, especially out east in Orient and Northwest Harbors,” he said.

But first they have to live through the next year, with more uncertainty than ever about the timing of rising water temperatures in relation to the scallop spawn.

Dr. Tettelbach has heard rumors that algae blooms or predation by blowfish could be responsible for this year’s die-off, but said the science doesn’t back up either of these theories.

A massive series of brown tide algae blooms in the mid-1980s nearly destroyed the Peconic Bay scallop population, which is still recovering from those blooms thanks to the work of the Peconic Bay Scallop Restoration Program.

There were no scallop-killing algae blooms in the Peconic Bay system this year, and blowfish eat juvenile scallops, not adults, said Dr. Tettelbach. And oyster growers said this year’s water quality led to one of the best harvests they’ve seen.

But one new threat does have him worried, and it’s also tied to climate change.

The cownose ray, a southern fish species that is believed to have destroyed scallop fisheries in North Carolina in the 1990s, has been making its way north with warming sea temperatures.

Dr. Tettelbach said the rays been found in Shinnnecock Bay and fishermen have seen them in Hallock Bay in Orient this summer.

“We just don’t know how many are out there,” he said. “We want to try to get more information.”

Dr. Tettelbach said part of the reason he suspects there could have been some predation by cownose rays is that, when scallops die due to environmental conditions, they leave evidence in the form of whole shells, with hinges attached. But rays suck scallop shells, crushing them into pieces attempting to get at the meat inside.

Researchers did pull up large numbers of dead adult scallops, with the hinges attached. But the numbers of dead scallops in some areas weren’t as high as they’d expected if the sole cause had been high water temperatures.

The past two years have been banner ones for Peconic Bay scallops, with 100,000 pounds of meat landing in each season, the biggest harvests since 1994.

“We’ve been thrilled with how everything is going,” said Dr. Tettelbach of restoration efforts led by the Peconic Bay Scallop Restoration Program, and their effect on the scallop rebound. “If we have a similar survival this winter to what we had prior to 2017 and 2018, I would hope it would be a pretty good year next year, but I don’t think it would be as good as those two years.”

With scallops in such short supply, retail prices are $30 per pound or higher, if they can even be found at local fish markets. But Dr. Tettelbach doesn’t think the price will be a deterrent for scallop lovers.

“People are buying them like hotcakes. It’s such an iconic species and delicacy,” he said. “People want them.”

But he cautioned baymen who might be tempted to harvest juveniles once they grow larger later this season that doing so will make replenishing the bays more difficult. It is illegal to harvest or sell Peconic Bay scallops that are smaller than 2¼ inches across and do not have an annual growth ring on their shell. That ring won’t appear until after the March 31, 2020 closing of scallop season.

“We’re concerned this year about the potential harvest of juveniles. There are some out there approaching 2¼ inches that do not have an annual growth ring,” he said. “If those are taken, you’re taking away from the spawning stock next year. I’ve heard stories from many people who say ‘the big bugs never survive to the next summer or fall,’ but there’s no evidence to back that up.”

The New York State Department of Environmental Conversation monitors Peconic Bay scallop harvesting, and they’ve maintained their usual opening-week presence on the water and dockside this week.

“DEC will continue to conduct enforcement patrols checking harvesters to ensure legal scallops are being harvested from open (certified) areas,” said the DEC in a statement Friday.

“To retain bay scallops, they must be over 2¼ inches in length from its mid-hinge to mid-bill and also display an annual growth ring. An annual growth ring demonstrates they have been able to reproduce prior to being harvested,” added the DEC. “An annual growth rings forms on the scallop valve (shell) where the stoppage of growth during the winter meets new growth that resumes in the spring. The annual growth ring is typically raised and easy to see. You can also check for the annual growth ring by running your fingernail from the shell edge to hinge; if it catches, this can be a good indicator of where the annual growth ring is. The growth ring can also be associated with a change in shell color and can typically be seen easier on the bottom shell.”

In the meantime, lovers of local food throughout the East End are urging consumers to support their local fish markets and baymen by purchasing other in-season local fish this winter.

“I feel terribly for the baymen. This is going to be such a tough year for them,” said Dr. Tettelbach. “Everybody has come to depend now on the scallop harvest.”

He also said this year’s bad news has given him cause for concern about the longterm changes to the ecosystem.

“I’ve been diving in the Peconics for over 30 years,” he said. “We’re now wearing 3mm wetsuits in the summer instead of 7mm. That’s anecdotal, but it’s real. A lot of people poo-poo climate change, but this is striking us right between the eyes. It’s pretty hard to ignore.”

“We need to stop hiding our collective heads in the sand and deal with this,” he added. “Climate scientists have said it is reversible, but we’ve gotta act now. This is not just business as usual. This is real and it is happening now and it is affecting people all over the world and locally.”