The White Sharks of Cape Cod

As white sharks return to the Cape, recreational fishermen are adjusting to the changing ecosystem.

white shark

The first shark appeared out of nowhere. On a calm midsummer’s day, Captain Ross of Cape Cod Charter Guys was fishing in 10 feet of water on Cape Cod Bay near Billingsgate Shoal. As one of his clients was finishing his cast and lifting his lure out of the water, a 12-foot white shark came straight up out of the water, a foot from the boat with its mouth open, gums pulled back and teeth bared. The clients jumped back from the gunwale in shock. Captain Ross had never heard of a white shark following a lure before.

After the adrenaline rush from that encounter subsided, Captain Ross headed to another fishing spot about four miles north toward Wood End. As he was reeling in a striper off his stern, a second shark made a downward-facing strike on the fish.
 
“Its back and tail came completely out of the water!” recounted Ross. “Somehow it didn’t get hold of the hook, but the force of that shark folded my rod down and jerked me right up on my tiptoes.” That one was smaller, probably a 10-footer. What was left of that striper can be seen in the photo that went viral on social media.

striper with white shark bite
Captain Ross displays what’s left of the striper taken from his line by a 10-foot white shark just a few feet off the stern of his charter boat in Cape Cod Bay last July. Cape Cod Charter Guys

While the experiences of Captain Ross and his clients that day were breathtaking, they were not extraordinary. Encounters between anglers and white sharks have become increasingly common in the waters surrounding Cape Cod. According to Diogo Godoi of Gorilla Tactics Sportfishing, white sharks regularly began taking fish off the lines on his charters about four or five years ago. Jason LaMagna of Got Stryper Fishing Charters told me, “It’s not quite an everyday experience, but it’s part of the norm now. It’s what all our clients want to talk about on the boat these days.”

How have these close encounters affected the charter-fishing experience? “I’ve never had a negative reaction from a client after seeing a shark or having one take a fish off the line. If anything, it spices up the day,” Godoi said. However, these encounters have caused charter captains to make some adjustments to the way they manage a day on the water. For example, LaMagna said, “I net everything now. I will not put my hands in the water to revive a fish because that would be like ringing the dinner bell. I certainly don’t let anyone go swimming off my boat anymore.”

Not all charter captains are concerned about the increase in shark encounters. Matt Perachio of Tighten Up Charters commented that, “If anything, I’d like to see more sharks. All the better to keep the growing gray seal population in check.” His remark brings us to the primary reason behind the recent influx of white sharks around Cape Cod: the abundance of gray seals, a fat-rich dietary favorite of this large apex predator.

Return of the White Sharks

White sharks have frequented New England waters during the summer and fall months for centuries. In 1865, Henry David Thoreau spoke of them in his meditative book about Cape Cod. With more than a little 19th century hyperbole, Thoreau wrote that locals “will tell you tough stories of sharks all over the Cape . . . how they will sometimes upset a boat, or tear it to pieces, to get at the man on it.” Back then and well into the early 20th century, Massachusetts had a healthy gray seal population to attract sharks.

In the April 2021 issue of this magazine, I published an article about the growing conflict between striper anglers and seals on the Cape and Islands, including a detailed account of the return of gray seals to Massachusetts waters. To recap, gray seals are large pinnipeds that can grow up to 10 feet long and weigh over 800 pounds. New England fishermen have always felt antipathy toward these animals, which they slaughtered with “nuisance killings” and a bounty system that persisted into the early 1960s until there were almost no gray seals left.

white shark predation attempt
“Once a seal sees a shark, the seal wins,” Greg Skomal said. This seal eluded its attacker just off the beach on Monomoy Island in November 2020. Courtesy Wayne Davis/Ocean Aerials

That began to change with the passage of the Marine Mammals Protection Act of 1972, which made it illegal to capture, kill, or harass any marine mammal. Gradually, gray seals that had survived in Canadian waters began to repatriate their range to the south. By the 1990s, they were returning to Massachusetts waters, and pupping colonies were established on Muskeget Island and Monomoy. Today, there are at least four established pupping colonies, and the gray seal population around the Cape has been estimated between 30,000 to 50,000.

Meanwhile, white sharks were facing threats of their own. Using bycatch data from commercial longline fishing and shark-killing tournament records, marine scientists estimated that the white shark population in New England waters declined approximately 80 percent between 1960 and the early 1990s. Of course, given the absence of seals during that timeframe, sharks wouldn’t have been motivated to come as close to shore as they do now.

The plight of white sharks began to improve when a federal fishery management plan was adopted in 1993 for all coastal shark species in U.S. Atlantic waters. In 1997, the white shark and a few others were listed as “prohibited species,” preventing anyone from catching and keeping them in the Exclusive Economic Zone, from three miles to 200 miles offshore. Then, in 2005, the Massachusetts Department of Marine Fisheries (DMF) went a step further by prohibiting capture of a white shark within three miles of shore, and again in 2015 with an emergency regulation prohibiting chumming, towing decoys, or cage diving for white sharks without a permit.

In other parts of the world where shark tourism is a popular activity (e.g., Gansbaai, South Africa; Isla Guadalupe off the coast of Baja California), these types of practices are used to attract white sharks. Unfortunately, habituating sharks to boats (and humans) as sources of food becomes a learned behavior with dangerous second-order consequences.

shark circles wounded seal
A white shark circles as a mortally wounded seal bleeds out just off Nauset Beach in October 2017. Wayne Davis/Ocean Aerials

As the gray seal population reestablished itself, the first reports of white sharks near the Cape began in the mid 2000s. Greg Skomal, senior fisheries scientist at DMF, initiated the Massachusetts Shark Research Program (MSRP) in the late 1980s, but its focus didn’t shift to white sharks until 2009.

“Seals were everywhere,” said Skomal. “We were getting more reports each summer of dead seals on the beach with wounds that could only be attributed to white sharks. I then got a call from a spotter pilot who saw white sharks off the Outer Cape.” That same year, Skomal and DMF marine biologist John Chisholm tagged five white sharks over the Labor Day weekend. So began a white shark research program whose scientific importance and impact on public safety have increased with each passing year. Through the summer of 2021, the MSRP has tagged 279 sharks, primarily with acoustic transmitters, and identified a grand total of over 400 sharks either by tagging or identifying unique markings on their bodies. The MSRP’s work has been providing many new insights into our understanding of a creature so often maligned.

Sorting Fact from Fiction

Back in 1975, composer John Williams’ haunting, two-note motif and director Steven Spielberg’s fictional portrayal of a giant man-eating predator terrorizing the summer vacationers on Martha’s Vineyard scared the bejesus out of millions of moviegoers and etched that cinematic trauma into our zeitgeist. Jaws has had an enduring and immeasurable influence on people’s perceptions and misconceptions not only about white sharks, but about sharks in general. Ever since, much of the shark coverage in mass media and Hollywood has fomented fear and skewed toward the sensational. Yet, ironically, it also provided inspiration to future marine biologists. Greg Skomal has said that the movie, and especially Matt Hooper, the folksy fictional shark biologist played by Richard Dreyfuss, was a source of motivation to devote his career to studying sharks.

AWSC Sharktivity smartphone app
With over 500,000 subscribers, AWSC’s Sharktivity smartphone app helps raise awareness of white shark activity around the Cape. This screen grab shows the 91 confirmed sightings for August 2021.

Putting fiction aside, what do we know about real white sharks? Often called great white sharks, the white shark (Carcharodon carcharias), is a broadly distributed coastal and offshore species inhabiting both tropical and temperate zones. Unlike most fish, they can keep some areas of their bodies warmer than the surrounding water. This enables them to range over vast expanses of the world’s oceans and swim to greater depths than many other shark species. Skomal has tracked five sharks in the open Atlantic through a broad temperature range that includes diving to depths of well over 3,000 feet.

Females can grow to 20 feet, weigh up to 5,000 pounds (males are somewhat smaller), and live for over 70 years. They are not able to bear young until their thirties. “No one has ever seen a white shark mate or give birth, so nobody really knows exactly where or how they do it. It’s one of the great mysteries of the species,” explained Megan Winton, staff scientist at the Atlantic White Shark Conservancy. Females have an estimated gestation period of 18 months, and the pups are born live. (This low and slow reproduction rate makes the species especially vulnerable to decline.) Newborn pups are four to five feet long, and litter sizes range from two to ten pups. They are on their own from the moment of birth – unlike mammalian apex predators (e.g., orcas, wolves), there is no parental investment in teaching pups to hunt; hunting skills are a combination of instinct and learned behavior.

Shark researcher Peter Klimley wrote that “baby white sharks have pointed teeth for seizing and swallowing prey, unlike the triangular and serrated teeth of adults used for cutting off pieces of meat.” Younger sharks have a fish-based diet until their teeth change when they’re about three years of age and their diet shifts to marine mammals. However, they are opportunistic carnivores, so it’s not unusual for adults to continue to feed on fish and squid.

While most vertebrates possess five senses, the white shark has an additional sixth sense: it can detect electromagnetic activity via a network of pores on its snout. This extra sense likely has a role in long-distance navigation, while also enabling it to detect and evaluate potential prey, even while closing within a meter.
White sharks are more cautious and selective predators than you might imagine. Skomal makes the distinction between a full predatory strike versus a more exploratory encounter with potential prey. When the shark is unsure of what it’s perceiving, it might choose to do a “test bite.” Researchers aren’t certain what they are testing for (taste, texture?), but it seems to trigger a binary decision: proceed with or abandon the attack.

acoustic receivers
In 2021, the DMF and AWSC deployed 50 acoustic receivers stretching from Monomoy Point up the eastern shore of the Outer Cape to Provincetown and along the shore of Cape Cod Bay to Sagamore. Data from these receivers are uploaded at the close of each season. The yellow stars indicate five live receivers that provide locations of tagged sharks in real time.

In many parts of the world, white sharks strike from below. In Massachusetts, where many seal attacks occur in shallow water, the sharks use different strategies. As Skomal explained, “Once a seal sees a shark, the seal wins, so the shark needs to use the environment to its advantage. If there’s deep enough water, it may go deep before it strikes, or it might use turbid water to disguise its approach. We’re just starting to understand this behavior.” But make no mistake about it: gray seals are formidable adversaries. According to Winton, they “have long, wicked claws and very sharp teeth, and they fight back. We see scars on sharks to prove it.” In a successful attack, the shark circles while the seal bleeds out. Only then will the shark approach and begin consuming the seal.

A New Research “Hot Spot”

In 2012, upon learning that the work of the DMF’s Massachusetts Shark Research Program relied on outside funding, Cynthia and Ben Wigren founded the Atlantic White Shark Conservancy (AWSC), a nonprofit organization based in North Chatham. Its mission is to “support scientific research, improve public safety, and educate the community to inspire white shark conservation.” Ms. Wigren, its CEO, explained that AWSC is the largest funder of white shark research in New England.

17-foot great white shark
A 17-foot female, the largest shark spotted in 2020, moves lazily alongside the Aleutian Dream just off North Beach Island in Chatham. John King steers the boat into position as Greg Skomal (on the pulpit) deploys an underwater drone with cameras. Wayne Davis/Ocean Aerials

Conducting research in the wild is a complex undertaking requiring the collection of data from sharks tagged with transmitters. However, before you can tag them, you have to find them. John King, who donated his boat, the 24-foot Aleutian Dream, to the AWSC and has been its captain since 2014, told me, “No one had ever tried following free-swimming white sharks with the aid of a spotter pilot in a small boat before.” At Skomal’s request, King’s boat was customized with an 11-foot pulpit and an entirely new method of shark tagging was born. Once a shark is spotted, the pilot radios its location and the Aleutian Dream closes in on it. Then, in the manner of a whaler with a harpoon, Skomal wields a tagging pole to expertly tag the shark. To date, Skomal has placed an assortment of tag types near the dorsal fin of over 250 sharks.

Tagging is only half the battle, though. Tracking a shark tagged with a transmitter requires an array of acoustic receivers mounted on buoys and securely anchored in place. Last summer, AWSC and DMF deployed 88 broad-scale acoustic receivers in Massachusetts waters, with 50 of those around the Cape. There are also five “live receivers” off the Outer Cape that detect tagged sharks in real time. Managing all these receivers requires a herculean effort to install them in May and retrieve them in November.

Data collected from the growing number of tagged sharks and receivers has already resulted in the publication of groundbreaking results. According to Winton, “We knew the sharks hunted seals close to shore, but we wanted to find out exactly how much time they spent in shallow water, so we used satellite tags to record temperature and depth data.” The study found that the tagged sharks spent 47 percent of their time in less than 15 feet of water, a finding that surprised even Skomal. “Really big fish don’t like to be in a shallow, dynamic environment,” he said. “There’s got to be a big energetic payoff for an animal that size to take such a risk. It tells me that they’re really invested in the strategy of feeding on seals.”

Winton is leading another study to project the population of white sharks. Scientifically determining their numbers around Cape Cod and, more broadly, in Massachusetts waters, will provide a numerical baseline of immense value to all future white shark research. For example, Winton and Skomal are working on a predator/prey study involving tagging sharks with camera tags that have an accelerometer in them.

“Although these tags last only a couple of days, lots of data is recorded. And, they have an embedded camera, so it’s as if you’re riding on the back of a white shark!” said Winton. Skomal added, “We’re getting the sense that these sharks spend a lot of time hunting and perhaps not so much time succeeding. If we can determine how frequently they feed and know their population size, then we can extrapolate the number of seals taken out of the seal population.”

Greg Skomal  applies an acoustic transmitter to a white shark
Greg Skomal applies an acoustic transmitter to a white shark from the pulpit of the AWSC research vessel, Aleutian Dream.

Another study, led by Bryan Legare of the Center for Coastal Studies in Provincetown and funded by the National Park Service and the DMF, focuses on white shark behavior and habitat use in shallow water at five beaches along the eastern shore of the Outer Cape. “The combination of a critical mass of sharks tagged with transmitters trackable via acoustic receivers, along with new developments in seafloor mapping that can detect how ripples and bars are formed and also measure currents and waves at different depths, allows us to measure the movement of sharks in fine detail in shallow water,” Legare said. As Skomal sees it, this study will help distinguish distinct types of predatory behavior across specific habitats, enabling researchers to predict where the sharks are most likely to spend their time.

Cape Cod has recently emerged as a “hot spot” for white shark research, one of just a handful around the globe. The implications of this go well beyond science to ecotourism and a growing commitment among conservationists to protect the evolving coastal ecosystem.

White Shark Tourism

Everywhere white sharks aggregate, people want to see them. With reports of shark sightings on the increase, a few charter captains saw an emerging opportunity to offer shark tours off the eastern shore of the Outer Cape. The first of those was Captain Darren Saletta of Monomoy Sportfishing out of North Chatham, who launched his first shark tour in 2014.

John King, who is on AWSC board and a member of the executive committee of the Center for Coastal Studies, carefully researched the shark tour businesses in South Africa and ecotourism businesses in other locations. He found that the key to success with these businesses is providing experiences allied with the scientists studying the ecosystem. That’s exactly what’s happening on Cape Cod, where the shark tours follow a similar process to the research vessel by relying on spotter planes to find the sharks and direct the boats to them.

Tyler Putney shark tour
Charter captain Tyler Putney treats his private shark tour clients to a close encounter with a white shark just off North Beach Island last July. Wayne Davis/Ocean Aerials

“These tours give insight into the shark’s natural behavior,” Winton said. “They aren’t manipulated in any way.” With the 2015 regulations preventing chumming and other forms of attracting sharks, the tours offer an authentic view into the life of this remarkable apex predator in its natural habitat. So far, the DMF has not seen a need to further regulate or require special permits for this relatively new form of ecotourism.

These tours are quite difficult to pull off, however, given all the environmental factors a charter needs to contend with to offer a successful experience to its clients. Before a tour is greenlit, the charter captain needs to assess fog, wind, sea conditions, seaweed, and water clarity, not to mention aviation conditions. Without the spotter plane, there can be no shark tour, which makes the cancellation rates significantly higher than typical fishing charters.

There are a growing number of private charter options for people wishing to view white sharks off the Outer Cape, but they are understandably pricey given the combined cost of a charter boat and a spotter plane. Depending on their length, 2021 rates for shark tours ran between $1,500 and $2,500 per charter.
When I asked Darren Saletta how he felt about the future of shark tourism, he paused and said, “Cautious. All fisheries tend to change.” He’s right. We’ve seen the striped bass fishery flourish in the late 1990s and early 2000s, only to decline sharply over the last decade. And what of the Atlantic cod fishery? Keep in mind, though, that all fisheries function within a broader ecological context.

A Changing Coastal Ecosystem

The return of gray seals and white sharks is changing the entire coastal marine food web in ways we’re only beginning to understand. Seals are eating huge quantities of sand eels and bottom fish while bedeviling sports anglers by disrupting the behavior and location of many of their favorite fish. Meanwhile, white sharks are feasting on seals as well as fish and are influencing the behavior and locations of both. Then, add in the impact of rising ocean temperatures causing a northward shift in the distribution of many species.

White sharks feeding
White sharks are feasting on seals as well as fish and are influencing the behavior and locations of both.

For now, let’s dispense with the notion that the coastal ecosystem is returning to some idealized natural state – nature is a far messier affair than that. And, humans have always intervened, sometimes with noble intentions like the Marine Mammals Protection Act and other times with indiscriminate slaughter of animals (like seals) that threaten commercial or recreational interests. But, what we’re seeing now off the Cape is something entirely new: the reemergence of an apex predator and a mesopredator (the seal), with minimal intervention from humans.

To better understand the potential of a healthy white shark population at the top of a fully functioning food web, we can look to another example of the introduction of an apex predator. Gray wolves were reintroduced to Yellowstone in 1995, some 70 years after their extirpation. In the ensuing years, the wolves have not only had a stabilizing effect on the previously unchecked elk population, but they’ve also triggered a “trophic cascade,” helping to reestablish vegetation that provides habitat for moose, beaver, and many bird species. The beavers, in turn, have improved the habitat for native cutthroat trout. In just over 25 years, the Yellowstone ecosystem has been transformed in some unexpected and wondrous ways.

Yet, people don’t tend to think about Cape Cod the way they think about Yellowstone, but perhaps they should. With 64 square miles of Cape Cod National Seashore, the Monomoy National Wildlife Refuge, a booming whale-watching business, the reappearance of a charismatic apex predator, and the emergence of a top-to-bottom natural food web, it’s possible to begin reimagining Cape Cod as a global destination for ecotourism.

“The stakes are high because we’re a robust, tourist-based economy,” said King. “Our pristine beaches and all the activities people enjoy on the water are our crown jewels.” Still, everywhere you go on the Cape these days, people are talking about the sharks—talk ranging from fear to respect to awe. If the goals of conservationists can be reconciled with public safety and commercial interests, Cape Cod’s marine ecosystem will continue to develop unimpeded. Seeing how that unfolds could be a once-in-a-lifetime experience.

14 on “The White Sharks of Cape Cod

  1. Pete Polachi

    The wolves at Yellowstone essentially ate the entire herd of elk that used to be so numerous anyone going in or out of the park at the gallatin Montana entrance would inevitably see dozens lounging around, even right next to buildings. The herd no longer exists, and overall elk populations in the park have declined so steeply that they’ve been granting Gray Wolf hunting licenses to experienced hunters in Montana and I believe also Wyoming, to cull the population back lol. Don’t get me wrong, reintroducing the wolves was a great idea and good for the park for many years but they’re such next level apex predators and efficient pack hunters that they’ve actually managed to go past restoring balance to the extent that intervention was needed. They’ve also become so numerous that many have been pushed outside the boundaries of the park and wound up killing valuable livestock that ranchers can’t afford to lose. Human intervention always has wacky consequences. Just ask the seal who stole a cow striper from my buddy last fall.

  2. Quint

    This shark, Swallow you whole. Fairwell and a due to fair Spanish ladies, Fairwell and a due to ladies of Spain, for we’ve received orders for the sail back to Boston.

  3. Matt Hooper

    All this thing does is eat, sleep, and make baby sharks.

    M.H. The Oceanographic Institute

  4. Henk van Gerwen

    Very good to have the sharks back in your waters. The nature back in balance should be the goal!

  5. Ralph daviet

    Messing with Mother Nature always seems to have its unintended consequences!

    1. charlie

      Why don’t they make them a game fish again and put a bounty back on the seals. There are too many of both and people are going to die because of it. Neither one was ever endangered and these people in the white shark conservancy are making a bundle and playing with peoples lives. They have these shark alarms and buoys,a lot of good they will do when a 2000 pounder is swimming away with someones leg

  6. charlie

    Why don’t they make them a game fish again and put a bounty back on the seals. There are too many of both and people are going to die because of it. Neither one was ever endangered and these people in the white shark conservancy are making a bundle and playing with peoples lives. They have these shark alarms and buoys,a lot of good they will do when a 2000 pounder is swimming away with someones leg

  7. Gordon Fletcher

    Very good article, however some things are being glossed over. The impact that the seals have had on recreational is fishing is enormous. An 800 lb seal has to eat a huge amount of sea creatures every day. I’d say 20 pounds would be a large under estimate. Multiply that by the number of seals and the real impact can be clearly seen. Any fisherman can tell you that the notion that seals eat “mostly” sand eels is a vast distortion of the truth. The effort needed to catch that many sand eels would leave them gasping on the beach 90%of the time. Chomping 2 striped bass would be so much easier but very bad for their “image”. The plain truth is that seals eat every kind of fish, the easier and bigger the better. The mere presence of the seals causes game fish to leave the normal areas they would inhabit. They do this for the same reason people don’t walk down dark alleys with $100 dollar bills stuck in their hat. When gamefish leave so do the visiting fishermen and all the commerce they create. Sharks are a very large problem for fishermen as well. Many of the things that fishermen do are very attractive to sharks. Standing in waist deep water reeling in a thrashing fish at dawn is a recipe for sharky attention. Having these sharks around is not welcome at all. Think of the uproar if lions started roaming golf courses.

    1. Bob

      Sorry the white sharks in their national habitat that have been here for millennia are ruining your vacation. Just stay on your yacht or on the beach next to your 5 million dollar house. This is what sharks do and they belong here. Every fisherman hates that it disrupts their livelihoods but they understand it.

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