Horseshoe crabs face ‘ecological extinction’ in Long Island Sound, due to harvesting and habitat loss


CALF PASTURE BEACH – Lured by the full moon rising over the Norwalk Islands on Tuesday evening, a 450 million-year-old swarm in formation lurked just below the waves lapping on the sandy beach.

Joe Schnierlein, a former marine biologist and high school teacher, dove through shins of water and pulled up the armored shell of a female horseshoe crab, one of hundreds of spider-like animals that chose that night to land and lay their eggs to spawn the next generation in Long Island Sound.

The full moon and its associated high tide – which provides good cover for horseshoe crabs to lay their eggs high on the beach – also attracted around 40 human volunteers, including Schnierlein, who came to place tags on the animals as they laid eggs, part of a scientific monitoring program that attempted to track populations of these ancient crabs in the Strait for more than two decades.

Led by staff from the nearby Sea Aquarium, volunteers like Schnierlein have been coming to this particular spot on the beach for years, where they say favorable tides and clear nights can help them find and tag more than one hundred crabs in about an hour. On other occasions, however, it can be difficult to find even a few dozen crabs.

“There have been good years, bad years,” Schnierlein said. “Is it because of the weather? You do not know.

Across Long Island Sound, researchers monitoring the results of these tagging efforts and others say horseshoe crabs are in decline, driven by a combination of habitat loss, pollution and commercial fishing. which threatens the role this species has played in the environment since before the time of the dinosaurs.

The Atlantic States Marine Fisheries Commission reported in 2019 that horseshoe crab stocks in the New York area, which includes Long Island Sound, were in “poor” condition, after a series of surveys showed their numbers have been declining since the late 1990s.

Jennifer Mattei, a biology professor at Sacred Heart University who has studied horseshoe crab populations for years as part of the Limulus Project, said the findings contrasted with more abundant populations farther south in places like that the Delaware Bay, where millions of eggs laid by the crabs serve as a vital smörgåsbord for migratory birds such as the endangered red knot, which flock to the bay in their thousands en route to nesting grounds in the arctic.

Although the Straits horseshoe crabs aren’t in danger of disappearing completely, Mattei said their numbers are so low they can’t handle the numbers of birds and other wildlife they do. elsewhere in their range.

“We don’t have that phenomenon here because there just aren’t enough crabs for it to happen.” said Mattei. “It’s a bit of what’s called an ‘ecological extinction’, where they just don’t feed the birds, they don’t feed the fish, because the eggs are scarce and buried and so they’re not available for most animals that use them for nutrition.

Prompted by concerns raised by Mattei and others, officials with the state Department of Energy and Environmental Protection began drafting new regulations last year to drastically reduce the annual harvest of crabs in the strait.

While crabs are harvested in some areas for biomedical research that uses their blue blood to test the purity of vaccines, the majority of those harvested off the coast of Connecticut are taken by a dozen licensed fishermen to be cut up and used as bait in eel and whelk traps, according to DEEP.

Fishermen were in disbelief at the new rules, arguing that volunteer efforts to tag and count crabs were failing to find them, leading researchers such as Mattei to underestimate the overall population.

“There’s more to it than they think,” said Bob Guzzo, a Stonington-based commercial fisherman. “I don’t think they’ve got the science quite right yet, (but) they’re not asking much of us, all they’re doing is restricting us more and more.”

This year, Guzzo said he has completely abandoned the harvesting of horseshoe crabs in favor of alternative, less regulated bait species such as the Jonas crab.

A few fishermen’s decision to find alternative bait may represent the population’s best opportunity to rebound, researchers say, after state lawmakers ran out of time earlier this year to issue a full moratorium on cutting the crop. of tens of thousands of horseshoes. crabs every summer.

“I didn’t do this work to take away people’s livelihoods, I want to manage the resources so they are sustainable,” Mattei said. “But what we found was that horseshoe crabs continued to decline for all of these various reasons, from habitat loss to pollution and harvesting, and that their role in the ecosystem and the environment has diminished considerably.”

In addition to regulatory changes, horseshoe crab advocates say public education is also key to raising awareness about the species and efforts to monitor and conserve their populations.

Bridget Cervero, a Sea Aquarium educator who led the group of volunteers at Calf Pasture Beach last week, said the program has garnered “massive” interest this year after such outings were limited over the past few weeks. first two years of the COVID-19 pandemic. .

As she addressed the group of volunteers around 11:30 p.m. on Tuesday, nearly all of the adults and children crammed into headlamps raised their hands to indicate that it was their first time marking horseshoe crabs.

The aquarium, which conducts two or three trips to the beach in May and June, requires first-time volunteers to attend a training session to learn about horseshoe crabs and how to collect them. correctly and apply the labels.

One of the newcomers, Jeff Spahr from Norwalk, said he grew up seeing horseshoe crabs while taking trips to nearby islands on his boat, but said such sightings have become less frequent in recent years.

“I always felt the population was dwindling and I felt bad about it, so I wanted to do something to help document it,” Spahr said. “When I saw this I jumped on it, it was awesome.”

For others, including roommates Andrea McKenna and Johnny Fremgen of Saugerties, NY, midnight excursions have become a regular summer activity and a way to tap into a love of nature.

“Seemed like a better way to contribute than your typical reduce, reuse, recycle,” McKenna said. “Even if it was squid, I’d be here doing it.”

Following years of volunteer tagging data, Mattei said she and her fellow researchers have been able to determine that horseshoe crabs tagged along the Connecticut coastline will cross the strait, but venture rarely outside its waters.

The discovery prompted regulators in New York and Connecticut to work together to craft similar limits on harvesting horseshoe crabs on both sides of the strait, Mattei said.

Horseshoe crabs have also found other allies in the conservation movement, including the Connecticut Audubon Society, whose members have called for a complete ban on commercial harvesting to help sustain migratory bird populations.

“The more horseshoe crab population we have here, the more fuel these birds will have when they stop here,” said Patrick Comins, executive director of the Connecticut Audubon Society. “If they don’t get the nutrition they need, they can’t get to their Arctic breeding grounds.”

On Tuesday evening, the results of the expedition along Calf Pasture Beach were encouraging, as the volunteers used the 180 beacons brought by Cervero in about an hour and a half.

As in a previous outing in May, Cervero said volunteers reported that most of the animals they found, including breeding pairs, were healthy and parasite-free. Once the animals are tagged, they are released back into the water so they can continue to lay their eggs.

“They are hardy animals,” Cervero said. “They’ve been around for 450 million years and they did it because they figured out how to live.”


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