Mark Royer/University of Hawaii
Many people are terrified of sharks, but when you look at the odds, those fears seem pretty silly.
The average number of people killed annually by sharks is estimated to be about six. (Roughly the same number die from heart disease every 12 seconds.)
"More people are killed by things like flower pots, lawn mowers, toaster ovens, deer, cows, and dogs each year," shark researcher David Shiffman told Smithsonian in 2013. "More people are bitten by other people than by sharks."
Of course, fear isn't rational - you don't see people giving toaster ovens the side-eye, and many other things that people are afraid of, including public speaking and spiders, are unlikely to harm you either.
Humans' fear of sharks, however, has done them a lot of harm.
The shark sport-fishing industry grew tremendously after the film "Jaws" was released in 1975. Soon after that, commercial fisheries started focusing on sharks, and a booming economy in Asia caused demand for shark fins to skyrocket. Shark populations around the world started to plummet, with more than a quarter of shark and ray species now at risk of extinction.
REUTERS/Feisal Omar
Many sharks are keystone ocean creatures - they're essential to the health of marine ecosystems, so you can't have a healthy ocean without them.
In order to reduce human-shark interactions while protecting sharks at the same time, researchers are using a variety of scientific experiments and common-sense strategies. Learning more about sharks may help us better coexist with them.
What to know when swimming
Education may not sound as sexy as a protective wall or suit, but it's the best way to limit interactions between sharks and people.
Shark bites (that's the term researchers prefer to "attacks," since it implies toothy curiosity, rather than aggressive intent) are extremely rare. But there are a few steps swimmers and surfers can take to make them even less frequent:
- Avoid areas that large sharks are known to frequent. You can't avoid sharks if you swim in the ocean - it's open water, after all. But more dangerous sharks are known to frequent certain beaches at specific times of the year. California surfers, for example, are more likely to encounter sharks in Mendocino County in October and November.
REUTERS/Hugh Gentry
- Learn the times of day and parts of water where you're more likely to encounter sharks. Sharks are most active at twilight and in the dark, according to the University of Florida's Natural History Museum. They also like steep drop-offs and the areas in between sandbars.
- Steer clear of certain types of water. In very murky water, it's easier for a shark to mistake a person for something else. Researchers also recommend avoiding waters that are being used by fishermen, since the bait can attract sharks. Waters where there's sewage may also attract the animals (that's a gross place to swim anyway).
- Don't panic. Splashing and panicking if you see a shark is more likely to confuse it and make it think there may be a prey animal nearby. And don't try to grab or harass the animals in any way - people provoke bites by doing this.
- Be aware of the presence of other animals. If you see an area of the water with diving seabirds, that probably means there are plenty of fish to eat there. And that means there could be sharks, too. The National Parks Service also says the seal population off the coast of Cape Cod has started to attract white sharks - so don't swim near seals.
- Play in the ocean in groups. Whether you are swimming, kayaking, or diving, sharks are less likely to approach a group of people than a solo individual.
Ways to make beaches safer for swimmers
Wikimedia, CC / Thomas Ehrensperger
You're not too likely to encounter this deep ocean swimmer.
There's no evidence that killing off sharks (known as culling) makes an area safer for swimmers. But there are a few things that have made a difference:- Changing the way humans dispose of garbage. Reunion Island, a popular resort territory off the coast of Madagascar, has seen a particularly high number of shark attacks. When researchers started to tag and track sharks there, they realized the animals were congregating where boaters and marina-goers dumped trash - right at the entrance to a populated beach.
People on Reunion Island have also experimented with walling off certain beaches with nets (while inspecting those nets to minimize the chances that turtles or other creatures get caught in them). Still, nets have been criticized for being ineffective and hazardous to marine life in other parts of the world.
- Moving sharks away from popular beaches. A study in Recife, Brazil found that using specialized fishing gear to catch potentially dangerous sharks and release them (still alive) far away from swimmers and surfers led to a 97% decline in shark encounters.
- Using drones to spot sharks. Off the East Coast of the US, researchers are using drones to spot great whites that are looking for seals. While it's not yet clear whether this technology will be effective in the Atlantic's dark waters, it has proved successful in Australia and California.
- Setting sharks up with Twitter accounts. Western Australia has tagged more than 300 sharks with transmitters that sound out their location - and tweet if they get near a beach or surfing area.
- Installing a shark repellent cable that emits an electrical pulse. South Africa has tried putting a cable that emits an electric pulse along a section of seafloor between a beach and open ocean. Sharks can sense electrical fields, so theoretically the pulse would be strong enough to bother them (and drive them away from the area), but not strong enough to harm them. However, no sharks showed up at the beach where this device was being tested, so it's impossible to know how effective it is. There's also not enough evidence to say whether specially painted wet-suits and surfboards can deter sharks either.
Because the chances of a shark bite are so small, however, most of these innovations are not necessary for the average beachgoer. And remember, we kill 100 million sharks a year, 11,000 every hour. They have a lot more to fear from us than the other way around.
Fisheries advise: tagged tiger shark detected by Leighton receiver at 03:09:00 PM on 28-Jun-2017
- Surf Life Saving WA (@SLSWA) June 28, 2017