It’s always struck me as odd how terrified many people are of sharks. It’s one thing if you’re a surfer or fisherman, but why would people living thousands of miles from the coast list the marine predators among their greatest fears?
Yet the recent explosive popularity of “Sharknado” — as well as the annual success of Shark Week, which began last night on the Discovery Channel — has continued to prove that humans are both fascinated by and petrified of these creatures.
In reality, you are more likely to be killed by your toaster than a shark … and if sharks were to disappear, it would be bad news for all of us. Here are just a few of the reasons why.
1. Sharks keep the food web in check.
Many shark species are apex predators, meaning they reside at the top of the food web. These sharks keep populations of the species they prey on in check, weeding out the weak and sick animals to keep the overall population healthy. Their disappearance can set off a chain reaction throughout the ocean — and even impact people on shore.
For example, a study found that large sharks have declined dramatically in the northwest Atlantic since the mid-1980s. The presence of fewer sharks led to a population explosion of species like cownose rays, which in turn depleted the region’s bay scallops. This was an important factor in the collapse of North Carolina’s century-old bay scallop fishing industry.
2. Sharks could hold cures for diseases.
It has puzzled researchers for years: Why don’t sharks get sick? (They do, of course, but not as often as other species.) Shark tissue appears to have anticoagulant and antibacterial properties. Scientists are studying it in hopes of finding treatments for a number of medical conditions, including viruses, cystic fibrosis and some forms of cancer.
3. Sharks help keep the carbon cycle in motion.
Carbon is a critical element in the cycle of life; as you might remember from high school biology class, all living things contain carbon.
By feeding on dead matter that collects on the seafloor, scavengers like deep-sea sharks, hagfish and starfish not only keep themselves alive, they also help to move carbon through the ocean.
In addition, research has found that, like trees, large marine animals such as whales and sharks sequester and store large amounts of carbon in their bodies. When they die naturally, they sink to the seafloor where they are eaten by scavengers, as mentioned above. However, when they are hunted by humans, they are removed from the ocean, disrupting the carbon cycle.
4. Sharks inspire smart design.
People have been practicing biomimicry — imitating nature’s designs to solve human problems — for many years. However, recent advances in technology have made it possible to go even further in pursuit of efficient design.
With a history spanning more than 400 million years, sharks can teach us a lot about speed and efficiency in the water. For example, Speedo recently designed a line of swimsuits that imitated the grooves in shark skin, called dermal denticles, which reduce friction drag.
Copying sharks could even lead to globally significant innovations. An Australian company called BioPower Systems has designed a device resembling a shark’s tail to capture wave energy from the ocean and convert it into electric power. As the world looks for clean energy alternatives to fossil fuels, use of this kind of technology could be one promising solution.
5. Sharks boost local economies.
Over the last several decades, public fascination with sharks has developed into a thriving ecotourism industry in places such as the Bahamas, South Africa and the Galápagos.
According to a study recently published in the journal Oryx, shark tourism generates about US$ 314 million per year and is predicted to more than double in the next 20 years. These activities — which support businesses like boat rental and diving companies — are said to provide 10,000 jobs in 29 countries. Several studies have indicated that in these places, sharks are worth much more alive than dead.
In addition to these benefits for people, it’s likely that sharks fulfill other roles in their habitats that we have yet to understand or appreciate.
Species are sometimes called the “building blocks of ecosystems,” Yet humans continue to remove these blocks without fully understanding the consequences. Up to 100 million sharks are currently killed every year, largely for the shark fin trade.
Think of the world’s biodiversity as a giant game of Jenga: if you keep removing blocks, eventually the whole thing will come tumbling down.
Molly Bergen is the managing editor of Human Nature. Check out the next blog in our Shark Week series.