Demon Fish (40 page)

Before heading out, Coetzee warned that great whites don’t just circle in the water with their fins jutting out. But within minutes of our anchoring and throwing out bait, an ominous, nearly black fin appears just yards away from the boat. The shark we had been anticipating—and fearing—had arrived.

By the time I manage to get an underwater look at a great white, my fear has dissipated. Maclean isn’t exaggerating when she says, “It’s you in the Zoo.” The cage is a solid piece of equipment, an assemblage of firm, crisscrossing bars that show no sign of failing. As Coetzee shouts, “Divers, look left,” I draw a deep breath and push myself down, whipping my head around to catch a glimpse of the shark heading for the tuna head Coetzee is dangling on a rope before it. The shark moves slowly, making lazy figure eights in and out of range of the cage. While there are plenty of whites in the area, they never congregate. One fish will come in for the bait, give up after a few attempts, and swim away. Then another will do the same.

The great whites that parade before us are elegant despite their size. They lack the hulking mass of the whale shark, along with the cartoonish markings. There is a seriousness to the torpedo-shaped bodies that slice through the water, a wedge of muscle ready to flex when necessary. And then the moment comes: a white lunges for the fish head, its teeth bared. While much of the diving experience smacks of being in a glorified aquarium, this is the one time when it feels, for an instant, as if we’re witnessing nature in its element. The shark’s teeth are jagged, and it manages to snatch a bit of the head before shoving off. It’s the money shot.

Everyone makes it into the cage but Kietzmann, who is held back not by fear but by seasickness. And the tourists go away with exactly the impression Maclean had predicted they would: reverence, and affection. It’s an odd sort of adventure tourism, whose proprietors depend on long-held stereotypes to lure customers but harbor a hidden agenda to unravel them at the end of the day.

Boarding a flight out of Cape Town a few days later, I happen to run into Richardson as he and his family are embarking on the same plane. “I loved it,” he reminisces about our dive. “It was surreal. There you were, in with the shark. You felt like you could reach out and tickle its tummy.”

Climbing up the stairs on the Jetway, he pauses to contemplate why sharks have such a terrible reputation. But even if it’s unjustified, he notes, it’s what brought him to Gansbaai. “Of course, if they didn’t demonize it, we wouldn’t have come. Now I get to go back and tell my friends, ‘I’ve been with a shark,’ and they’ll think, ‘What a man.’ ”

And with that, he makes his way with his wife and daughter to their designated seats, headed home to tell his fish tale. He has managed to conquer a formidable predator while allowing the animal—like himself—to live another day.

CONCLUSION: SHARK NIRVANA

I know the human being and fish can coexist peacefully.

—George W. Bush, campaigning as a presidential candidate in Saginaw, Michigan, September 29, 2000

I am still optimistic about sharks.

—Peter Klimley, professor at the University of California at Davis

T
he northern Line Islands are, quite literally, in the middle of nowhere. It is a place where sharks rule.

A series of Pacific atolls lying roughly one thousand miles south of Hawaii, the Line Islands remind us of what the sea used to look like. To get there from Honolulu, you must ride on a motorboat or ship, on open ocean, for five days. Its uninhabited Kingman Reef is pristine; the other islands are slightly more populated in quick succession until you reach Kiritimati, or Christmas Island, with a population of fifty-one hundred.

National Geographic’s Enric Sala led an expedition to the atoll in 2005 and returned in 2006. What he saw was something unlike anything he had ever seen: a reef so dominated by sharks and other top predators that other fish were nowhere to be seen, since they know that to be seen is to be eaten.

“There is a landscape of fear,” he tells me as we sit on a beach in the Dominican Republic. He is drawing in the sand, to try to give me a sense of how bit by bit humans have degraded the world’s oceans. The other fish are elusive at Kingman, he explains, because they know the risks if they come out.

Sharks make up 75 percent of the fish biomass at Kingman Reef. At Kiritimati, by contrast, top predators make up just 19 percent. While diving at Palmyra, an island not quite as unpopulated as Kingman, Sala witnessed firsthand what it meant to exist in a perfectly honed predatory system. In an effort to conduct a comprehensive survey of the marine organisms on the reef, he caught a damselfish and tucked it into a Ziploc bag, which he in turn deposited into the nylon mesh bag he was holding at his side. Then he reached for a grouper about half a foot long, hoping to fit it into another Ziploc bag. During the course of this tussle the fish began to shake, and suddenly—whoosh—a couple of blacktip sharks came along, aiming for the grouper. “They started biting at it,” he recounts. “Then a whitetip and gray reef shark came.” At this point Sala decided to abandon the mesh bag with the two fish still inside it and swim away to a safe distance where he could observe the scene. “They destroyed the mesh bag and ate the fish, right through the Ziploc. These guys were really hungry. There’s a lot of competition. Everything that is injured or sick is eaten within seconds there.”

Kingman Reef looks like few other atolls in the world: the only ones that rival it are those that help compose the Phoenix Islands, another Pacific archipelago that, like the Line Islands, is split between the American and the Kiribati government. Not only is Kingman Reef supremely healthy, with corals covering the seafloor to such an extent that it’s nearly impossible to see the sand, but the fish have been so sheltered from human beings that they view them as a curiosity. When Sala and his colleagues began diving there, the snappers and groupers appeared to be fascinated by the strange sight of these alien creatures, checking out the Spaniard’s ponytail and the other scientists’ equipment.

“I bet it was the same feeling Darwin had when he stepped on Galápagos for the first time,” Sala says. “It was a totally new experience.”

There’s just one problem: as soon as you add humans to the mix, the sharks start disappearing.

Sala and his collaborators published the results of their expedition on February 27, 2008, in the online edition of
Public Library of Science
Biology
. It is the most comprehensive analysis ever of what they call “reefs without people.” That same edition included a commentary from Nancy Knowlton and Jeremy B. C. Jackson, coral experts affiliated with the Scripps Institution of Oceanography and the Smithsonian Institution, saying the study has redefined the way we should view corals worldwide. Examining coral reefs without taking into account what they were like before humans degraded them, they analogized, was like “trying to imagine the ecology of tropical rainforests by studying environmental changes and interaction among the surviving plants and animals on a vast cattle ranch in the center of a deforested Amazon without any basic data on how the forest worked before it was cleared and burned.”

When you imagine the coral reefs of old, or even the sea just a hundred years ago, sharks play a starring role. We think of oceans, and wild landscapes in general, as a neat pyramid in which there are a small number of big predators on top and many small predators below. The study Sala and his colleagues have published suggests just the opposite: an undisturbed ecosystem resembles an inverted pyramid with plenty of large predators on top and fewer small predators below. The animals at the top clear out the weakest animals in the population and keep the midsize predators in check. Without the top predators, the waters begin to look completely different.

Ransom Myers provided the first evidence that it was worth keeping sharks around, and his students continue to build the case for it. Boris Worm, one of Myers’s closest collaborators, co-authored a 2008 paper in the journal
Trends in Ecology and Evolution
that elaborated on this phenomenon. Worm and his colleagues identified how the “landscape of fear” that Sala talks about reverberates throughout ecosystems worldwide. In Prince William Sound, Alaska, harbor seals are so scared of Pacific sleeper sharks that they forage in shallower areas, which in turn keeps the walleye pollack population intact. The tiger sharks in Shark Bay, Australia, intimidate large herbivores such as sea turtles and dugongs enough that these prey species shift their distribution depending on the season: that keeps the area’s sea-grass habitat from being overgrazed.
¹
Sharks, Worm explains, “have a huge impact on the ecosystem because they were there before everything else. When everyone came into the system as an evolutionary baby, sharks were already there and had figured it out.” Nowadays sharks keep other, smaller predators in check. “Sharks are being kind of ‘the cop on the street’ in the ecosystem,” Worm analogizes.

Rachel Graham makes the identical pitch when she lobbies local officials in Belize to put protections in place for sharks. “Think about what would happen to your town if there was no rubbish collector,” she tells them. That would be a problem, they respond. “Now imagine in a month’s time nobody’s arrived in a month, and the rubbish’s piled up,” she continues. “And the policeman hasn’t arrived.” Graham’s point is clear: sharks may not perform the most glamorous function in Belize’s waters, but their role keeps the marine ecosystem humming. Take out the sharks, and the species that Belize’s citizens really care about—the ones that make up the bulk of the commercial fish trade—will suffer.

In the same way that scientists now use computers to predict how climate change will reshape the planet by the end of the century, researchers are modeling the implications of taking large sharks out of the ocean. One group found that a simulated decline of tiger sharks in Hawaii’s French Frigate Shoals would boost the numbers of seabirds, turtles, monk seals, and reef sharks, thereby triggering a rapid decline in tuna and jacks. A similar exercise showed that taking sharks out of Floreana Island in the Galápagos would harm several commercial reef fish species, since the ranks of toothed cetaceans, sea lions, and other predators would swell accordingly. Just as we are conducting an uncontrolled experiment on the earth by emitting an unprecedented amount of carbon dioxide into the atmosphere, we are altering the sea with the same sense of abandon, by yanking out what Francesco Ferretti and his colleagues call “a relatively stable force in ocean ecosystems over evolutionary time.”
²

Researchers have recently discovered this same behavioral ripple effect in the northern Rockies. When Americans wiped out gray wolves in Yellowstone and the surrounding areas in the late 1920s, the willow and aspen trees stopped reproducing. Then, after the Fish and Wildlife Service reintroduced wolves to the region in the mid-1990s, the willows and aspens began to reappear: in time songbirds and beavers came back as well. It wasn’t just that the wolves were eating the elk, but the elk became sufficiently frightened of wolf attacks that they stopped grazing all winter on the banks of streams, where the aspens and willows grow. Even local mountain lions changed the way they roam, and often take longer routes on rougher ground so if a wolf comes along, they can climb up a tree for shelter. Ed Bangs, who heads the U.S. Fish and Wildlife Service’s gray wolf recovery program in the northern Rockies, explains that all the other animals in the ecosystem recalibrated their behavior once one of the top predators returned. “Everyone was like, ‘Oh, yeah, wolves, I remember how to deal with that.’ ”

A few months before Worm’s paper came out, a group of nineteen scientists, led by Benjamin S. Halpern at the National Center for Ecological Analysis and Synthesis, published an article and map in
Science
capturing the extent to which humans have left a footprint on the sea. They culled seventeen global data sets for twenty marine ecosystems and came to a stunning conclusion: “No area is unaffected by human influence.” None. Nearly half of all coral reefs experience “medium high to very high impact” from humans, they concluded, with areas in the Mediterranean, the South and East China seas, and the North American Eastern Seaboard ranking among the hardest hit.
³

Sometimes humans’ impact on the sea is visible, like in the aftermath of the April 20, 2010, explosion of the Deepwater Horizon in the Gulf of Mexico. The massive oil spill that spewed out of BP’s doomed exploration well not only covered brown pelicans and northern gannets but also soaked sharks swimming well below the ocean’s surface. While it will take years to assess the full extent of the accident’s toll, there is no question that sharks—possibly some of the most imperiled ones, such as bigeye thresher, dusky, and oceanic whitetip—suffered along with other wildlife in the region. Two months after the accident ten whale sharks showed up just twenty-three miles southwest of Sarasota, Florida, raising the possibility that these animals had been forced to seek refuge in a different part of the ocean as pollution contaminated the Gulf of Mexico.

We attack sharks in subtle ways, and in blunt ones. In one of the most telling incidents of just how dramatically the “man bites shark” story has evolved in recent years, a Coney Island lifeguard had to come to the aid of a juvenile shark—most likely a sand tiger shark—that was being attacked by a crowd of Labor Day beachgoers in 2007. As New York’s
Daily News
put it, “Tender-hearted muscleman Marius Mironescu rescued a 2-foot sand shark from a mob of panicked swimmers, grabbing the wriggling fish in his arms and—in a neat reversal of the usual scenario—swimming out to sea with the stunned animal.” Mironescu estimated that between seventy-five and a hundred people had encircled the small creature and begun attacking it. “They were holding on to it and some people were actually hitting him, smacking his face. Well, I wasn’t going to let them hurt the poor thing,” he told the
Daily News
. In the end the shark proved less forgiving than the lifeguard who came to its rescue: while it played dead during the attack, as soon as Mironescu began doing a backstroke with the fish in one hand, it revived and tried to bite him.
⁴