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6.21.10

Unraveling the Great White Hype

Modern technology is key to understanding the mysteries and science of sharks, says marine biologist Greg Skomal, the Discovery Channel’s “shark guy” and one of the world’s leading shark experts, who talked to us at his office in Oak Bluffs before leaving for Saudi Arabia this spring to tag sharks.

In the eyes of many, the Island will forever be associated with great white sharks, thanks to the 1975 thriller Jaws, but in reality the chances of a shark attack in Vineyard waters are extremely slim. Also, many other species swim nearby, including the blue shark, above – although frightening in appearance, it tends to be fairly timid around humans, according to Greg Skomal.
Greg Skomal

A large photo of a Greenland shark hangs over Greg Skomal’s desk at the old lobster hatchery in Oak Bluffs, and the beast looks big, but not particularly toothy. At a mention of this, Greg pulls the jaw of a Greenland shark from a freezer. It’s about a foot across, and he explains that the top rows of dozens of small pointy teeth are for grabbing onto seals. The bottom rows of teeth are flat and odd looking, almost like a corn cob, and once the shark seizes its prey, it shakes the body back and forth so the bottom teeth act as a saw to remove a hunk of flesh. It’s a graphic description that makes the listener glad not to be a seal in Greenland.

In his twenty-three years as senior biologist for the Massachusetts Division of Marine Fisheries, Greg has worked on a variety of issues, anything of interest to the agency: wetlands, herring runs, all manner of aquatic minutiae. But sharks take up the bulk of his time, and sharks have put him on the front page of newspapers and have taken him around the world. “Never forget the selling power of the shark,” he says. “Sharks attract attention. Sharks sell.”

And the Vineyard sells it. We buy bait at Shark’s Landing and slake our thirst at Sharky’s Cantina. Oak Bluffs hosts a shark fishing tournament. Scenes from a certain iconic 1970s summer movie and its successors hang over the Island like a collective memory. The Kintner boy serves us tuna melts at the Wharf Pub in Edgartown. His slap-happy movie mother stands behind us in line at the Capawock Theatre in Vineyard Haven. If one perpetrates a hoax about shark sightings, one can get arrested by the blue-clad grown-up who was the fake-fin boy (this actually happened in 2008), and “He made me do it!” will not get you off the figurative hook. I’ve sailed many times with the lovelorn Timmy from the sailing-themed sequel. The Island even attracts people who host Jaws-themed weddings.

But for all their menace and popularity, sharks are a mystery. When asked how sharks are doing, Greg cautions against generalizing. “It’s important not to lump them together, [but] to look at individual species or stocks.” And it’s difficult to look at individual species and stocks because “long-term, species- specific data is poor,” mostly because information on fish tends to come from fishermen, and people haven’t historically fished for sharks. “If a species isn’t exploited, we don’t have the data,” he says. Sharks only became targeted by fishermen some twenty-five years ago.

Shark fishing boomed in the 1980s for a variety of reasons, according to John Mandelman, a research scientist specializing in elasmobranchs (sharks, skates, and rays) at the New England Aquarium in Boston. While other fish stocks were declining, sharks were still relatively bountiful, and the international market for shark meat and fins was developing. But another factor was that recreational shark fishing became “trendy,” John says. “There’s a hunting-esque aspect to it. To put it crudely, it’s a testosterone-fest....This was post-Jaws and pre–Discovery Channel.” Public education through events such as the Discovery Channel’s Shark Week have since changed the image of sharks, John says, from “evil, menacing white sharks” to a fascinating family of more than four hundred species (some only as big as cigars) that needs conservation. “We still fear them, but it’s a healthy fear...a respectful fear.”

John also speaks in disclaimer-filled phrases about sharks. “Management [of sharks] is limited by a lack of data, so we do take a cautionary approach.” Sharks are unpredictable, notes John, and unlike other species of fish, which tend to have regular behaviors, “it’s difficult to predict how and when you’ll catch these species.”

Greg Skomal, John Mandelman, and their colleagues are attempting to remedy that paucity of data through a variety of means, the most visible of which is tagging live sharks. Tagging five great whites off Chatham last September gained a lot of attention, and Greg shows off a tag that rode along with a great white – recording location, depth, water temperature, and light levels – before disengaging and bobbing to the surface in January. The tags have shown the migration patterns of the great whites, allowing scientists to fill in some of the many knowledge gaps for these secretive animals. As it turns out, the great whites, like many Vineyard visitors, head south when the weather turns chilly and spend the winter in Florida.

All of which means, for the Vineyarder, that there are indeed great white sharks in the waters around here. Greg says that estimating population trends for great whites is impossible, but there are arguably more great whites around the Islands now than at any time in hundreds of years, mostly because there are more gray seals here. Nearly extirpated at the end of the seventeenth century and considered a pest by fishermen, gray seals were persecuted until the Marine Mammal Protection Act of 1972. The now-protected population has expanded into new territory, including Muskeget Island between the Vineyard and Nantucket, where Greg says 80 percent of the gray seals in the United States are now reared in the relative peace they require for breeding. In 1991, researchers recorded twelve gray seal pups on Muskeget; in 2008, they numbered roughly two thousand. Great whites love a gray seal dinner, so, as Greg says, it may be “not so much a change in white shark population but a change in where they are. They might have found a new restaurant, maybe an old diner from three hundred years ago.”

Sightings of great whites are increasing, but that may be the result of more people looking for them, and sightings of great whites are notoriously unreliable. A fourteen-foot great white was confirmed in the Elizabeth Islands in September of 2004, and in 2008 a spate of unconfirmed Vineyard sightings, including the previously mentioned confirmed hoax, rang alarm bells in the media. But Greg and other shark experts are extremely wary of great white sightings. Basking sharks, for example, are very large yet harmless filter feeders and are often mistaken for great whites. Imaginations can run wild, Greg notes, and few people can tell a good story to a wide-eyed audience about their encounter with a mild-mannered filter feeder.

If you seek a shark story of your own, Buddy Vanderhoop, Aquinnah fishing charter captain and Island raconteur, reports doing a couple of “shark charters” yearly. He takes clients about ten miles south of Noman’s Land, and with the abundance of sharks, he says, “I can make your arm dead [from reeling in sharks] in an hour.” Of sharks in general, he’s seen in recent years “about the same number, but more great whites.” He saw six or seven whites in 2009, mostly in June and early July near Noman’s, where he also reports a lot of seals. “About five years ago near Block Island, I saw five [great whites] eating a dead, nasty-smelling whale....Whenever you see a dead whale, you see between two and ten of them.” Buddy says with a chuckle, “They really like eating that crap.”

Even with great whites around, the danger of a shark attack is close to nil. John Mandelman notes that since the eighteenth century, “only a small handful of attacks have occurred in New England waters” – three of them fatal, with the last occurring more than seventy years ago in Buzzards Bay off Mattapoisett. Though white sharks could conceivably attack people near shore, the makos and blues that might take a bite out of a person tend to stay well out to sea, and the ill-tempered bull sharks that account for many of the attacks in the southern U.S. don’t usually come this far north.

While sharks pose little threat to people, the reverse is not true. Sharks are generally long-lived and do not reproduce quickly, so the increase in commercial and recreational fishing since the 1980s has impacted certain shark populations dramatically. “Many species have encountered declines, and we’re not exactly sure of the extent of that. But we could come to a point of no return,” says John Mandelman.

Management of shark species occurs on the state, regional, national, and international levels, and it gets complicated, especially for pelagic species like makos and blues that range all over the Atlantic and are heavily fished. Blue shark numbers seem to be doing okay, but makos seem to be declining. Greg estimates fishermen from thirty different countries fish for makos in the Atlantic, and there is no international agreement on the management of the species. And while the U.S. is often painted as the big, bad bully on international environmental issues, John says, “In general, sharks in U.S. waters are well managed.” Since the U.S. is a country without a huge shark harvest, Greg says, “We’re kind of the little guy around the table.”

Porbeagles represent a slightly more successful example of international management. Canada heavily fishes porbeagles, a cold-loving and overfished shark, and has implemented a modest recovery plan. Only about 1 percent of the porbeagle catch is by U.S. boats, and conservationists would like that number reduced to zero, which wouldn’t do much to help the poor, beleaguered porbeagles, but would set an example of conservation.

Greg mentions that opponents of the Monster Shark Tournament want to set a similar example by stopping the tournament. “It’s exactly the same argument [as with porbeagles]...more philosophical than scientific.” The Monster Shark Tournament, held every July in Oak Bluffs by the Boston Big Game Fishing Club, annually sparks protest from the Humane Society of the United States and other groups and individuals opposing the event. The shark anglers, if they abide by tournament rules – which are stricter than government regulations – aren’t affecting the shark populations in a meaningful way. “But,” Greg says, “it’s really the spectacle people disagree with,” a spectacle that includes large, dead sharks hung up by their tails in front of cheering crowds. As for his take on the tournament, Greg gives a practiced answer: “I can’t let my personal feelings influence the position of my agency.” To the Division of Marine Fisheries, the Monster Shark Tournament is simply an opportunity to conduct research, such as data on weight, and tissue and stomach-contents samples.

But for Greg, a live shark is better than a dead one. “My research has evolved from cutting up dead fish,” which he admits still plays an important role, “to working more with live animals – their behavior, their ecology, how they relate to their environment.” Technology, like the data-collecting tags, allows him to do more non-lethal research.

Tagging basking sharks in 2008, for example, led to the discovery that they are “much more migratory than we thought....We knew they left; we just didn’t know where they went.” Since basking sharks feed on the same foods as right whales, it was assumed they followed right whales to Florida in the fall. Turns out they continue moving south of the equator and dive to depths of more than three thousand feet, perhaps to stay cool, maybe to breed, or for some other reason. While the tags tell him where the behemoths are traveling, they don’t tell him why. He reported his research for the scientific journal Current Biology, and it also was written up in Wired. “What sets Greg apart is not only is he representing the state and sharks in the media, but he’s also well respected in the scientific community,” says John Mandelman.

The demands of his job have Greg constantly scurrying around his ramshackle office, fielding phone calls, microwaving coffee, and looking for things misplaced. “You get to a point in your career,” he says, “when you’re no longer proactive, or reactive, but retroactive.” Greg is, to put it mildly, a busy man. His second-story office boasts a lovely view of Lagoon Pond, but he’s turned his computer monitor away from it to avoid the distraction. Of the challenges of managing species that range all over the ocean, he says, “It’s a lot, and it’s complex, and I’m involved at every level.” He sighs and glances out the window. “I find myself in a lot of meetings.”

What does Greg Skomal do when he’s not stuck in meetings or chasing sharks all over the eastern seaboard? He chases sharks all over the world. And he dives with them. “It’s what I love to do.” Noting that the state can’t reasonably justify sending him to the Caribbean to tag black-tip and lemon sharks, he does it on his own time. He headed to Saudi Arabia in May to tag whale sharks and has dived with the aforementioned seal- sawing Greenland sharks under the arctic ice.

It’s hard to spend time with Greg without bringing up Jaws, and after an hour-plus of self-restraint, I couldn’t resist. Greg smiles at the question. “It’s one of my favorite movies,” he says. It even influenced his choice of professions. “Hooper was so cool,” he says of Richard Dreyfuss’s shark-chasing scientist. Greg credits supportive parents with allowing him to study such a fascinating creature when he was a student, and good fortune that he eventually became a real-life Matt Hooper. “I cut my teeth, if you will, on sharks,” he says with a contagious smile.

Shark Conservation and Management

All species of sharks, despite huge differences in biology, used to be managed as one fishery: sharks. As commercial landings of sharks improved species-specific data in the 1990s, marine-life managers divided the species into groups. And as information continues to come in, specific species are now broken out for individual management.

The key to management of a species is the “stock assessment,” which details, as much as the data will allow, how a breeding population is faring. Greg notes the assessment for blue sharks, for example, says Atlantic stocks are “healthy,” though as soon as he says that, he corrects himself. “They never say ‘healthy,’” Greg explains. “They say ‘not overfished’ and ‘overfishing is not happening.’” The two key benchmarks are whether the population is: (1) overfished, that is, already significantly in decline, and (2) being overfished, that is, fishermen are currently taking enough fish to cause a decline. A stock may be overfished even though overfishing is not currently happening, or may not yet be overfished even if overfishing is happening.

The stock assessment for makos, according to Greg, states that they may be overfished and that overfishing is happening; therefore regulation is the next step. Makos, as a pelagic fish, roam all over the ocean, so management is handled by the International Commission for the Conservation of Atlantic Tunas (ICCAT), which regulates tuna and “tuna-like fish,” including pelagic sharks. Forty-eight countries are parties to ICCAT, and Greg estimates thirty of them fish for mako, with the U.S. only accounting for 5 or 6 percent of the harvest, so “there’s nothing we can do unilaterally.” While Greg and his fellow scientific advisors to ICCAT may have a clear and concise idea of how best to manage the mako, political and economic factors come into play, and “how that translates to management is where it gets fuzzy.” For example, last year a U.S. proposal to cap shortfin mako landings at 2008 levels was not adopted, as other countries wanted to exempt mako sharks taken as by-catch from the restrictions. (By-catch is unwanted fish caught during commercial fishing for another species.) Since by-catch is the leading cause of mortality of shortfin mako sharks, this exemption would have rendered the proposed regulation toothless.

The porbeagle, a cold-water shark that primarily stays up north, is overfished and possibly being overfished by the Canadian fleet. Canada has come up with a management plan that allows landings of two hundred metric tons of porbeagle and estimates the recovery of the species in eighty to a hundred years, an exceptionally long time (U.S. law typically requires a twenty- to forty-year recovery). That level of harvest is also so high it leaves very little margin for error. “But when you’re sitting around the table with forty other countries, and they’re all breaking the rules, except a couple including the U.S., it’s easy for Canada to say ‘at least we have a management plan,’” says Greg, who notes that Japan, Taiwan, and Spain catch the most sharks overall.

While well-traveled sharks like makos and porbeagles pose an international management issue, the U.S. does control the fates of stocks that stay close to U.S. shores. The Atlantic States Marine Fisheries Commission found that sandbar and dusky sharks were “overfished and being overfished,” and established very strict protective measures, basically shutting down those fisheries. But given sharks’ slow reproductive cycles, recovery could take thirty to forty years, and even that may not be enough. Sandbar sharks use the Chesapeake Bay as a nursery, and the Chesapeake is in poor health. “We can control, as fisheries managers, fishing mortality. What we can’t control is the Chesapeake Bay....We’re just now learning how dependent they are on estuarine areas that need habitat protection,” Greg says. He notes that the Endangered Species Act (ESA) requires protection of critical habitat, which could force measures to clean up the Chesapeake. “There may be some teeth in the Endangered Species Act,” he says without irony, but he thinks that an ESA listing for shark species would occur only after all fisheries management options have been exhausted.

There is no stock assessment for the smooth dogfish, a coastal species, but the population trends seem to be pointing downward, and stock assessment could indicate a need for regulation. Smooth dogfish aren’t valued here in Massachusetts but are fished extensively in the southern U.S., as fishing fleets targeting sharks are more developed there.

In general, shark fisheries management seems to have followed the pattern of other species: Assume there is no problem until it becomes glaring. But there is hope. Greg notes that recent iterations of the Sustainable Fisheries Act have put fisheries managers “in a better position to be proactive and cautionary” with fish stocks. John Mandelman agrees that despite a lack of data, fisheries managers are trying to “take a cautionary approach” with sharks, to help prevent crises from arising, rather than responding to crises. And that would be good news for both sharks and fishermen.

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