Demon Fish (26 page)

To figure out what shark lassoing entails, I must hang over the side of a motorboat that Ellen Pikitch has commandeered for research. Pikitch started out as a mathematician in college but became drawn to studying fish during grad school, even though she pursued her doctorate in landlocked Indiana. She speaks in the often flat tones of a Brooklynite and approaches her work with clinical precision, hoping to discern the sorts of mathematical patterns she studied earlier in her career. But Pikitch is passionate about two fish in particular—sturgeons and sharks—and her insatiable curiosity has prompted her to spend more than a decade conducting the longest-running shark survey in the world. To survey sharks properly, Pikitch and her team must tag them. And in order to tag sharks methodically, lassoing is required.

Naturally, one must perform this rodeo maneuver with some degree of skill, to guarantee that the subject in question doesn’t bite your hand off. There’s a straightforward way to ensure this doesn’t happen: first and foremost, make sure the shark has gotten hooked on a longline before you begin to lasso it. Many fishing vessels use lines that stretch for miles, but Pikitch and her colleagues rely on a line that measures a few dozen yards instead. They suspend fishing line baited with at least fifty hooks between two buoys, and then let it sit for a couple of hours to maximize the number of sharks that get caught in the line. Establishing a longline with baited hooks is the best way to catch sharks, as opposed to dragging a large net through the water that sharks could tear apart with their teeth. After the sharks are caught on the hooks, the lassoing can begin.

Once we’ve pulled up a line with a shark hooked on it, one of Pikitch’s colleagues holds the fishing line near the shark’s snout while the lassoer (me, in this case) grabs a rope that’s been knotted to form a noose. At this point the shark is floating in the water, parallel to the boat, so the entire procedure can transpire with the least amount of damage to the fish. With my left hand, I grab the dorsal fin to steady the shark while slipping the noose around the shark’s tail. Then I rapidly bring my left hand over to anchor the knot while pulling the rope tight, and, voilà, the shark has been properly lassoed.

This is anything but easy: during the entire procedure, the shark is focused on escaping my grasp. After taking over lasso duty on Pikitch’s boat, I am faced with the undeniable fact that not only are sharks not as dumb as they’ve been historically portrayed but even the reassuringly named nurse shark is a fighter.

Shark wrangling gives you an acute sense of these animals’ muscular bodies and the extent to which they can maneuver themselves in the water to elude any potential foe. On top of all that, grabbing a shark tail that’s swaying back and forth and covered in denticles is akin to having a baseball bat covered in sandpaper rub up and down your hand.

There’s a simple reason why we’re lassoing sharks today: it’s the easiest way to keep a shark pinned down if one is hoping to implant a radio transmitter in its body, which is what Pikitch and other researchers are planning to do. The fact that they need to resort to such elaborate tactics suggests how difficult it is to study sharks in the first place. They spend their lives underwater, where it’s hard to spot them, and they move fast. If one gets close to them, they might attack. None of these attributes make them nearly as easy to examine as, say, lab rats.

Pikitch is the kind of woman who actually craves run-ins with sharks. She divides her time between the Upper East Side and Stony Brook, but spends much of her work life in habitats such as Glover’s Reef, which she first began visiting in the mid-1990s. At the time, Pikitch was starting up the Wildlife Conservation Society’s marine program, and she was investigating the idea of establishing a research station on an island on the atoll called Middle Key, which a British noblewoman named Claude Kinnoull had left to the nonprofit. One day she was hanging out on the dock, chatting with Archie “Chuck” Carr III, a fellow WCS scientist, when she spotted two baby lemon sharks darting in and out under the pier.

“You don’t have baby sharks unless there’s a nursery,” Pikitch thought to herself. She soon set out to answer a basic question: What kinds of sharks, and how many, spend their days navigating the more than 750 patch reefs that make up Glover’s Reef, and is this pattern changing over time? This straightforward query, unfortunately, can only be answered if you can deploy enough technological gizmos on fish with sharp teeth.

The methodology of tagging—which has been applied to both terrestrial and marine creatures in recent years—has dramatically expanded scientists’ understanding of sharks. These devices can range from the mundane—plastic spaghetti strips with numbers, which simply let researchers know if they’ve recaptured an animal—to the high-tech, $3,500 satellite tags that can track where an animal has traveled, how deep it has gone diving, and how much energy it has expended in the process. Quite simply, these devices allow scientists to track marine life once it disappears below the surface, which amounts to a revolutionary advance.

This sort of information is so valuable in part because it gives scientists a sense of what parts of the ocean need to be sheltered more than others. Faced with the enormity of the sea, and the many different demands on it, conservationists are trying to identify the most ecologically valuable regions so they can establish marine protected areas. That way they can strike a deal with competing groups such as commercial and recreational fishing interests: leave these parts of the ocean alone, and you can exploit the rest.

Pikitch and her top assistants, Demian Chapman and Elizabeth Babcock, have been tracking their sharks with fairly straightforward, inexpensive monitoring equipment, spaghetti tags and radio transmitters, both of which can be applied to a shark once it’s lassoed. The spaghetti tags help researchers identify individual animals once they’re recaught, while the acoustic tags send radio signals that provide scientists with a sense of where a shark has traveled over time.

Once I’ve conducted the lasso operation with Chapman’s assistance, the scientists first record some basic information about the shark we’ve secured to the side of the boat. Using a simple band of measuring tape, they record the shark’s species and gender along with three separate lengths for the shark, because different researchers rely on different measurements. The first measurement captures the distance between a shark’s snout and the upper part of its tail, the second goes from the snout to the fork in its tail, and the third reaches from the snout to the tail’s end. Then it’s time for a quick surgical operation.

While keeping the shark secured in the water, Chapman makes a surgical incision about an inch long, right next to the dorsal fin. This allows him to insert an acoustic tag that will send a unique signal every time the shark swims within 1,640 feet of the nearly two dozen radio transmitters the team has stationed throughout the reef. With a few swift motions Chapman stitches up the incision, and we prepare to release the shark, taking care to make sure it doesn’t savage us in the process. I loosen the noose, he clips the hook with a pair of pliers, and I yank the rope back, sliding it easily over the shark’s tail. Then it’s off, thrashing furiously as it leaves behind the researchers who detained it from its usual cruising activity.

One of the oddest aspects of surveying sharks is that, in the end, it’s still fishing: you never know what you’ll wind up getting. In order to get a sizable variety of sharks, Pikitch and her team fish at night as well as during the day, since different species are active at particular times of day.

Because Glover’s Reef is full of shallow patch reefs, negotiating the waters at night without wrecking the boat amounts to a feat in itself. Only one man seems equipped to do this: Norlan Lamb, a Belizean fisherman who has worked on Pikitch’s project for nearly a decade. While Lamb uses GPS maps to get a general idea of how to negotiate the reefs, he relies mainly on instinct to avoid a shipwreck. He sometimes wears his sunglasses at night—it’s sort of a Zen approach, from what I could glean from our conversations.

Once Lamb has zipped across the reef to the study site, the researchers begin to check the line they set earlier in the day for sharks. The first shark that appears is a pregnant sharpnose: when it makes it onto the deck, its babies are squirming visibly inside, their small bodies forming clear and shifting outlines on her stomach’s surface. The shark’s eyes sparkle in the reflection of the assorted headlamps pointed in her direction; after Chapman and Babcock place a simple spaghetti tag on her, they let her go. Then they turn their attention to two male Caribbean reef sharks caught on the line; since both of them have been tagged in the past, they just jot down the tag numbers and identifying characteristics before releasing them. Still, even this basic summary requires the whole lasso routine, which at times doesn’t go so smoothly.

Once the scientists manage to tag their random collection of sharks, it’s up to the fish to let them know what’s happening underwater. The twenty-two monitors sit at the bottom of the sea for six months at a time, and before long these relays begin to blend into their surroundings in the way that a shipwreck does. The team refers to one of its relays as a “lobster farm” because, in Chapman’s words, “it’s got little wee lobsters all over it.” Another is so covered with algae it looks more like the outcropping of a reef than a piece of electronic equipment. But how they look is, ultimately, irrelevant. All the researchers care about is what signals they receive and transmit back to the research station.

After a decade of surveying Glover’s Reef and acoustically tagging more than fifty sharks, Pikitch and her colleagues can draw some basic conclusions. The sharks they find here stay in the atoll year-round: unlike some pelagic species, which roam far and wide, these animals display a remarkable fidelity to these waters. But they defy expectations in some respects. As Chapman observes, “These sharks are thought of generally as shallow, coral reef sharks.” But the acoustic tags testify to something different. One of the sharks they tracked dived down twelve hundred feet into water that was just thirty-nine degrees Fahrenheit. “You throw some technology at it, and find they live way down deep,” he says, adding that technology has “almost completely rewritten our understanding of their life history and biology. If you read shark books from a decade ago, large tracts of them are incorrect.”

Researchers used to think great white sharks were largely coastal dwellers; now they know these creatures are pelagic as well, capable of crossing vast stretches of ocean. They had believed sharks of all species could conceive only through copulation; Chapman has proved them wrong. And now that scientists are capable of attaching sensors to sharks that track their dives below the surface, researchers are beginning to understand how low the sharks go. A decade ago conventional wisdom held that Caribbean reef sharks live almost exclusively up on top of the reef, but tagging now proves they regularly dive anywhere from four hundred to a thousand feet below the surface.

The sharks in Bimini confounded the scientists’ expectations in a number of ways: nurse sharks have the reputation of being “couch potatoes,” in Pikitch’s words—they’re the sharks you’re most apt to run into if you’re snorkeling in a reef, since they often just rest at the ocean’s bottom—but according to radio tracking they’re fairly active. In July 2004 the team tagged a young female they describe as “Nurse Shark 3333”: this shark circumnavigated the entire reef, which spans 116 square miles, several times within a 150-day period. Caribbean Shark 3348, an adult male tagged in May 2004, proved to be a little more adventurous. At times during his 150-day tracking period this shark left Glover’s Reef entirely: at one point he swam nearly nineteen miles to Lighthouse Reef, where a separate set of researchers picked up his acoustic signal on their equipment. These results suggest that if Belizean authorities established stringent marine reserves in Glover’s Reef that were off-limits to fishing, they would protect the sharks from harm, since the fish tend to remain in the same general area. More broadly, now that it’s clear some pelagic sharks can cross ocean basins, international policy makers need to start thinking of ways to regulate fishing activities on the high seas.

Glover’s Reef, one of just four coral atolls in the Western Hemisphere, already enjoys some shelter from exploitation as a UNESCO World Heritage site. At the moment 30 percent of the reef experiences no fishing at all, and authorities prohibit gillnetting and long-lining—the more damaging fishing techniques—throughout the rest of the reef. Gill nets—massive mesh operations anchored by a lead line below and a float line on the sea’s surface—catch anything and everything that swims into their path, earning them the nickname “wall of death.” As a way of making peace with local fishing interests, the researchers have worked to construct a sort of shark park: part of it is off-limits to fishing, while a “general use zone” allows only artisanal fisheries, which generally inflict less damage than large, industrial-scale fishing operations. When local authorities initially set the rules, they were more focused on banning industrialized fleets than protecting Pikitch’s study subjects. “It just happens it’s worked bloody well for sharks,” Chapman observes. But the scientists are now pushing for even more restrictions, and local government officials have indicated they’re willing to expand upon the current regime. In 2007, the local fishery management council proposed banning shark fishing entirely in Glover’s Reef. Rachel Graham, a Wildlife Conservation Society scientist who lives full-time in Belize and has surveyed a broader range of sharks there, has spent years working with authorities there in an effort to ban shark finning nationwide.

“They still have a chance here in Belize,” Pikitch insists, even though she knows there’s a limited amount of time for activists to protect the reef. The top predatory shark populations within Glover’s Reef have remained stable between 2000 and 2007, according to her survey, which is no small achievement given the rise in shark catches elsewhere in Belize. But other reefs don’t enjoy the same level of protection, and they’re the ones that are coming under increasingly intense fishing pressure.