Jaws

06.15.11

Sharks Are Scary But Not That Dangerous

Sharks have a reputation that they’ll never live up to. You have a better chance of being killed by malaria or whooping cough.

As summer begins, familiar beach rites start up again. But along with the sunscreen, picnic coolers, and car caravans, there is the lurking fear that has dominated the American psyche since Jaws first struck movie screens 36 years ago: What about a shark attack? The number of reported shark attacks worldwide increased 25 percent in 2010, fueled in part by a series of strikes off the Egyptian resort of Sharm el-Sheikh, heightening the sense of dread beachgoers often feel when they approach the water’s edge.

The fear of being attacked from below the surface, by a hidden foe, taps into our most primal instincts. There are other lethal animals we might encounter in the wild—grizzly bears or tigers or … but we can see them coming. Sharks, by contrast, operate in a foreign territory where we visit from time to time. Their ability to launch a surprise strike renders us defenseless.

Here’s the truth, America: the sooner we make our peace with sharks, the better off we’ll all be.

This is not to say sharks are harmless. They are predators whose skills have been honed over millennia, and from time to time, they mistake humans for their target. They’ve got multiple rows of sharp teeth and when their teeth  break off or become worn, new ones grow in; they can detect the beating heart of creatures under the water’s surface or buried in the sand; and the bite force of a modern great white is more than three times the strength of an African lion.

And while some sharks consume tiny plankton and others eat seals, they do make unprovoked strikes on humans a few dozen times a year. Last year there were 79 attacks worldwide, according to the International Shark Attack File, the highest number since 2000 (when there were 80). But there were still only six fatalities, compared to an average of 4.3 during the past decade.

Sharks do make unprovoked strikes on humans a few dozen times a year. Last year there were 79 attacks worldwide. But there were still only six fatalities.

How does that compare to other causes of death, both globally and in the United States? Snake bites account for more than 100,000 annual fatalities, reports the World Health Organization. And according to the Centers for Disease Control’s 2007 statistics—the latest figures available—five Americans died from malaria, nine from whooping cough, and 613 from the accidental discharge of firearms during that year.

And what about the global epicenter of shark bites, Volusia County, Florida, which consistently leads the world in terms of reported shark attacks year after year? It had 17 unprovoked strikes in 2007 and 22 in 2008. But surfers continue to trek there undeterred, because the waves are good and the waters host blacktip and spinner sharks, which often exact only minor injuries. “It’s far from being the most dangerous place in the water,” notes George Burgess, who directs the Florida Program for Shark Research at the Florida Museum of Natural History and compiles the International Shark Attack File.

So it’s worth entertaining a counterintuitive thought. What if sharks were our ally, rather than our enemy? While all the scientific evidence suggests that sharks spend more time closer to shore than previously thought—whether one lives in New York City, Monterey, or Cape Town—new research also shows we’re better off imitating them than obsessing over their ability to strike a lethal blow. Predating dinosaurs by more than 200 million years, sharks have developed several qualities that make them unparalleled ocean predators. And with a little luck, these adaptive techniques can work to our advantage.

Sharks’ electroreception—which stems from a network of tiny, fluid-filled sacs in their snouts and chins known as ampullae of Lorenzini—allows them to sense electromagnetic fields generated by a fish’s beating heart or gills. Now scientists are scrutinizing this voltage-charged gel to see if they can build a better battery. University of San Francisco Physics Professor Brandon R. Brown has extracted the material from dead sharks to gauge its thermal sensitivity, while Case Western Reserve University Nanoengineering Professor Alexis Abramson is trying to develop a synthetic gel with similar thermoelectric properties that could be used to convert waste heat.

In addition to helping us power our cars, imitating sharks could lead to swifter ships and more advanced underwater sensors. Their armored skin, which has crowns covered with enamel, has inspired swimsuit clothing and offers the promise of faster vessels resistant to biofouling. Now that researchers from Mote Marine Laboratory’s Center for Shark Research and Boston University’s marine program discovered that sharks hunt prey by sensing the differences when their smell hits each nostril—they call it “smelling in stereo”—they are looking at whether they can use this same steering algorithm to develop odor-guided robots to track oil plumes and chemical leaks underwater.

Even more important, sharks maintain the ocean’s natural balance by clearing out ailing animals and keeping mid-level predators in check. A 2007 study led by the late marine biologist Ransom A. Myers found that between 1970 and 2005, the number of scalloped hammerhead and tiger sharks off the East Coast fell by more than 97 percent, and bull, dusky, and smooth hammerhead sharks declined by more than 99 percent. During that same time nearly all of the sharks’ prey species exploded: the cownose ray population there rose to as much as 40 million. These rays devour bay scallops, oysters, and soft-shell and hard clams, and by 2004 they had nearly wiped out adult scallops in the North Carolina sounds, prompting the state to close its century-old bay scallop fishery.

But in areas where sharks thrive, like the Pacific’s Marianas Trench and Phoenix and Line Islands, so do coral reefs and the fish that live within them. Healthy oceans, in turn, provide much of the protein we need to eat as well as help regulate our climate.

Some shark-based inventions may never materialize, and it’s hard to stomach the idea of letting lethal animals roam free. But seeing sharks in a new way may be the best thing for our survival, as well as theirs.