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Adriano Rodrigues has swum with all kinds of sharks in his two-plus decades diving off Cape Cod and Block Island. Yet he experienced a first in Buzzards Bay this June: He was spearfishing for black sea bass, when a massive shark approached him with its mouth wide open.
“I first thought it was a great white, for the size of it,” he said.
As the shark passed within feet of Rodrigues, the diver saw massive gill slits and tiny, hooked teeth within its maw, before it slammed shut. Rodrigues then identified it as a harmless basking shark, grabbed onto it, and rode the shark several feet underwater before letting go.
A lot of people are seeing fins on South Coast waters lately. On a Father’s Day weekend fishing trip, a bunch of large gray sharks surrounded Hilario Gomes’ boat off Westport.
“The captain that’s been doing this for the last 30 years, even he said he’s never seen anything like it,” Gomes said.
And in early June, several 20-foot sharks approached Perry Long’s boat when he went out to check his lobster pots in Westport with his wife.
“You see a dorsal fin coming at you, and it’s gray and big, we immediately think of ‘Jaws,’” he said.
Neither of these two fishermen had anything to worry about, either. The fish they saw were also identified by authorities as basking sharks.
Basking sharks are an endangered species that visits southern New England waters in the spring, summer, and fall. They filter-feed on zooplankton, swimming with their mouths open to catch these tiny organisms in their gills. They do not attack humans.
They are commonly mistaken for white sharks, given their size, shape and tendency to breach the surface, said John Chisholm, an adjunct scientist at the New England Aquarium’s Anderson Cabot Center for Ocean Life. 2024 has been the best year for local basking shark sightings in more than a decade.
“Last month, almost every white shark sighting I got was actually a basking shark,” Chisholm said.
Numerous local shark sightings — and a growing number of white sharks being detected off Cape Cod — may have South Coast residents concerned about encountering a great white this summer. Yet experts say it is unlikely they will find a white shark in area waters.
Two state-tagged white sharks have been detected within Buzzards Bay over the past decade, both in 2018. Just over 20 have been detected near the mouth of Buzzards Bay over that same period, according to the Atlantic White Shark Conservancy’s White Shark Logbook.
“The probability of dangerous sharks being in Buzzards Bay — from Westport to Bourne — is really very low,” said Greg Skomal, a shark biologist with the Massachusetts Division of Marine Fisheries.
Local shark scientists suspect hot water temperatures and a small seal population generally keep great whites away from the South Coast during peak season, in the late summer and fall. Buzzards Bay has been warming in the summer with climate change, a trend which regional authorities project will continue. So the scientists do not expect masses of white sharks to arrive anytime soon.
And while the local basking shark sightings are notable, there have been similar spikes in past years. “This isn’t out of the norm,” Chisholm said.
Still, local researchers are tracking the numbers and distribution of sharks in southern New England as waters warm. They urge South Coast boaters, swimmers, and fishermen to enjoy the presence of these sharks, but be cautious. There is always a chance that it is a great white.
“Anytime you go into the ocean, you are venturing into a wild environment,” said Atlantic White Shark Conservancy research scientist Megan Winton.
Basking sharks and the South Coast
Basking sharks are among the few shark species that frequent the South Coast. And to Chisholm, they are the Rodney Dangerfield of sharks.
“They get no respect,” he said. “They’re really fascinating sharks. But everyone wants to see a white shark.”
Basking sharks are the second-largest fish in the world, growing up to 40 feet long, and weighing more than 5 tons. They are one of three shark species that feed on plankton, and scientists estimate they can live for roughly 50 years. They are found in both the Pacific and Atlantic oceans.
The International Union for Conservation of Nature lists the species as endangered. Its global estimated population, in the tens of thousands, is declining as of 2018.
Basking sharks have been hunted worldwide throughout the centuries for their oily livers and fins. Studies show fishing and boating resulted in the loss of more than 50% to 80% of basking sharks worldwide in the 20th and 21st centuries.
They were given legal protections from fishing in many parts of the world in the 1990s and 2000s, including the United States and the European Union.
Researchers say there are signs that basking shark populations are slowly stabilizing and recovering in parts of the North Atlantic.
The fish seem to migrate cyclically, following blooms of zooplankton. Basking sharks come to New England in the spring and summer, before moving south in the Atlantic in late fall and winter.
They captivate scientists because of what we don’t know about these creatures.
This includes the logistics of their extraordinary long-distance migrations; some basking sharks tagged off Massachusetts in the summer have been seen off Brazil in the winter, Chisholm said.
And the sharks, which generally stay close to the surface while living in coastal New England waters, reside in the ocean “twilight zone” while they move into Caribbean and South American waters — between 650 and 3,300 feet below the ocean surface. They stay in those deeper waters throughout their time down south.
For years, scientists thought basking sharks sunk to the bottom of the North Atlantic in the colder months, and hibernated or searched for food down there.
“We didn’t know they traveled that far,” Chisholm said.
Scientists do not know why basking sharks migrate as far as they do, what they do in the twilight zone, nor why they surface at all — though feeding, mating rituals, and parasite removal are suspected.
The South Coast sees basking sharks every year. Yet the number of sightings fluctuates, and there is no discernible trend.
“There are good years and bad years,” Skomal said.
And while 2024’s number of sightings may seem unusual, other years have seen many local basking shark reports, like 2013.
“It’s not an every year occurrence,” Chisholm said. “But we’ve seen this before.”
Researchers caution that the appearance of basking sharks locally may not be a sign of global —or even regional — species recovery.
Female basking sharks can take 20 years to reach sexual maturity. Researchers believe they produce litters of just a few pups, and estimate gestation takes two to four years. So a quick rebound is not expected.
And while people may think more sightings of basking sharks off the South Coast suggests a large increase in population, it could also be that more people are reporting sightings, and that some sharks are concentrating around local zooplankton blooms.
“There’s a lot of questions, things we don’t know about them still,” Chisholm said.
Sharks and coastal Massachusetts
Scientists do not have a sound estimate for the number of sharks frequenting coastal New England. Yet reported sightings and animal tag data show we get a lot of them.
“New England is a very rich shark area,” said Atlantic Shark Institute executive director Jon Dodd.
More than 15 shark species have been detected in Massachusetts waters, including thresher sharks, porbeagle sharks, and white sharks.
Many are migratory, and some are year-round residents. The range of mild water temperatures — and abundance of prey — in the warm months make the region an attractive habitat for a variety of sharks.
Still, shark numbers are lower than they were centuries ago, before the advent of commercial fishing. And despite an exploding number of detections and sightings in recent years, scientists say the overall number of sharks off Massachusetts does not seem to be growing significantly. Likely, more people are reporting their sightings, and more sharks are tagged.
“They’re here every year, but people have not really been aware of them,” Chisholm of the New England Aquarium said.
Chisholm said protected species of sharks in the Northwest Atlantic are starting to rebound — including basking sharks, sandbar sharks, and dusky sharks — and are a part of the reason for more sightings.
Skomal, the state fisheries manager, has tracked sharks across the Atlantic for more than 35 years. He said existing data does not suggest any major increases in most shark populations off Massachusetts over the past few decades.
The lone exception is the growing number of white sharks off Cape Cod in summer.
“There is a definite, increasing, decadal trend there,” Skomal said.
White sharks are highly migratory, and the International Union for Conservation of Nature considers them a vulnerable species.
In the Atlantic, they move into New England in the late spring and summer as waters warm, to hunt seals and other prey. They leave New England when the waters get too cold, moving to the Southeast and the Gulf of Mexico in the late fall and winter.
The Outer Cape is a summer hotspot for white sharks, given its abundance of seals. Approximately 800 white sharks visited the Cape from 2015 to 2018, Winton said.
The number of white sharks in the Atlantic seems to be growing, scientists say, after an estimated loss of up to 80% of the population with fishing pressures in the 1970s and 1980s.
They attribute this recovery to federal legal protections for seals enacted in the 1970s, and federal and state protections for white sharks enacted in the last 30 years.
White sharks rarely visit Buzzards Bay.
“The South Coast in particular is not an area where they spend much of their time,” Skomal said.
The likely reason, Skomal said: fewer seals and hotter water compared to the Cape.
Buzzards Bay summer water temperatures often heat up to 80 degrees Fahrenheit, past the preferred range for seals, Winton said, and far past the preferred range for white sharks, who like waters between 50 and 75 degrees.
White shark activity on the South Coast has been detected early and late in the season, and seems to appear when the animals are migrating, Winton said.
And as summer water temperatures in Buzzards Bay climb with climate change, it’s likely to become even less hospitable to white sharks, Skomal said.
White shark attacks are also infrequent in the South Coast. The last fatal attack in Buzzards Bay was in Mattapoisett, in 1936.
Still, Winton said, South Coast residents should not let their guards down. They should abide by the Atlantic White Shark Conservancy’s “shark-smart behaviors”: avoid splashing around a lot, swimming with shark food, or swimming in cloudy water off the coast.
“Anytime you’re venturing into a wild environment where large predators occur, you want to take precautions,” she said.
Climate change and new shark visits
Regional shark researchers are keeping an eye on changing shark numbers, species and behaviors as the climate changes and protected populations recover.
“There already seems to be differences in what we’re seeing out there,” Winton said.
Northwest Atlantic waters have been heating at some of the fastest rates of anywhere in the world. Species that live in southern Massachusetts waters — like sandbar sharks — are starting to be sighted in Cape Cod Bay, Skomal said.
Spinner and blacktip sharks — which prefer warmer waters of the mid-Atlantic and Southeast— are starting to appear off of Rhode Island, Buzzards Bay, and the Islands, Chisholm said.
October — which used to feature freezing cold waters and few sharks — is now one of the busiest times of the year for white sharks on the Cape, with waters staying warm throughout the month, Winton said. A few white sharks stuck around into January this year, and also in 2023.
As for basking sharks, Skomal said, it’s “entirely plausible” that the intense storms that the South Coast has seen in recent months — along with warm summer waters — are fueling large zooplankton blooms, and attracting basking sharks close to shore.
Strong storms are only becoming more common in the area with climate change.
Meanwhile, people can enjoy watching basking sharks this year, Dodd said.
“We love seeing them,” he said. “I hope we have the same conversation a year from now, saying, ‘Hey, guess what? It’s two years in a row.”
Email environmental reporter Adam Goldstein at agoldstein@newbedfordlight.org.
