Here's the time of day you're most likely to get bit by a shark, and other tips for wary swimmers
Mark Royer/University of Hawaii
Many people are terrified of sharks, but when you look at the odds, those fears seem a bit silly.
The average number of people killed annually by sharks around the world varies by a few, but most estimates are in the range of around four. (That's roughly the number of people who die from heart disease every eight seconds.)
"More people are killed by things like flower pots, lawn mowers, toaster ovens, deer, cows, and dogs each year. More people are bitten by other people than by sharks," shark researcher David Shiffman told Rose Eveleth, writing for Smithsonian in 2013. You don't see people giving toaster ovens the terrified side-eye.
Of course, fear isn't rational — many of the things that people are most afraid of, including public speaking and spiders, are unlikely to do you any harm. Unfortunately, our fear of sharks has done a lot of harm.
Mark Royer/University of HawaiiThe shark sport fishing industry went nuts after the film "Jaws" was released in 1975. Soon after that, commercial fisheries started focusing on sharks as 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 at risk of extinction.
In order to reduce those incredibly rare human-shark interactions and at the same time, protect sharks (keystone ocean creatures that are essential to the health of marine ecosystems — you can't have a healthy ocean without them), researchers are using a variety of scientific experiments and common-sense strategies. What we've learned about sharks can hopefully help us better coexist with them.
The goal is to prevent shark bites. (That's the term researchers prefer to "attacks," since that word generally implies aggressive intent instead of toothy curiosity, which is what usually causes a shark to bite a human.) While these bites are so rare that they aren't really a problem, there are a few steps that can be taken to potentially make them even less frequent.
Educate swimmers — and don't swim at certain times
Education may not sound as sexy as some kind of protective force field, but it's the biggest thing that can limit interactions between sharks and people.
Mark Royer/University of Hawaii
Here are a few things swimmers should know:
- Avoid spots 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 there are certain beaches that more dangerous sharks are known to frequent at specific times of year. California surfers are told that they are most likely to encounter sharks in Mendocino County in October and November, for example.
- You're more likely to encounter sharks at certain times of day. They're most active at twilight and in the dark, according to the University of Florida's Natural History Museum.
- Avoid certain types of water. In very murky water, it's easier for a shark to mistake a person for something else. Researchers also say to avoid waters being used by fishermen, as the bait can attract sharks. Waters where there's known sewage may also attract the animals (plus, that's a gross place to swim anyway).
- Don't panic. Splashing and panicking if you do see a shark is more likely to confuse it and make it think there may be a prey animal there to check out. And certainly don't try to grab or harass the animals in any way — people provoke bites by doing this.
Mark Royer/University of Hawaii
Active interventions
In certain places, it's more common for people to encounter sharks, which has led researchers to look for more active strategies. There's no evidence that certain popular ideas like killing off sharks (known as culling) make anything safer for swimmers. But here are a few things that have made a difference.
- Figuring out why sharks bites are happening in a certain area and seeing what can be changed. Reunion Island, a popular resort territory off the coast of Madagascar, is one of those places that has seen a particularly high number of shark attacks. Dealing with the problem there has been complex and contentious, but one of the measures that made a difference was tagging sharks and realizing they were congregating where boaters and marina-goers were dumping trash — right at the entrance to a populated beach.
Mark Royer/University of HawaiiReunion has experimented with other measures too, including using nets to wall off certain beaches, while inspecting those nets daily to try to minimize the chances that turtles or other creatures end up 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 can be effective. A study in Recife, Brazil, found that using specialized fishing gear to catch potentially dangerous sharks and release them away from swimmers and surfers (still alive) led to a 97% decline in shark encounters.
Mark Royer/University of Hawaii
Technology
There's not enough evidence yet to say whether many of the cool sounding technological innovations out there — shark repellent or specially painted wetsuits and surfboards — can actually prevent a shark from checking a human out to see what they're doing flailing about in the water.
But there are other types of technology being tested too.
- Off the East Coast of the US, researchers are using drones to see if they can spot great whites that are looking for seals. Drones have been effective for this use in Australia and California, so the question now is how they handle the Atlantic's darker waters.
- Sharks on Twitter. Western Australia has tagged more than 300 sharks with transmitters that sound out their location — and a tweet if they are near a beach or surfing area.
https://twitter.com/mims/statuses/747279499469819904
Fisheries advise: tagged white shark detected by Strickland Bay (Rottnest) receiver at 12:04:00 PM on 27-Jun-2016
- South Africa has tried testing a shark repellent cable that emits an electrical pulse. The idea is that the pulse is strong enough to bother the sharks, which can sense electrical fields, but not strong enough to harm them. The issue with testing this so far has been a common one — no sharks showed up at the testing beach, so it's impossible to know how effective it was.
And that's the thing. The chances of a shark bite are incredibly small, and in many of the places that people fear sharks the most, people still never see them. We can talk about technology that's trying to prevent shark bites as much as we want, but most of it is not necessary for the average beachgoer.
Mark Royer/University of Hawaii
That doesn't mean that you should make yourself a target. Swimming over a trash dumping point on Reunion Island still sounds like a bad idea; spear-fishermen who use chum to fill the water with bloody baitfish know they're increasing their chances of a shark encounter.
So sure, avoid, risky areas and behaviors. If you're a surfer in a spot with a great white spotting program and you know there's a shark near you, get out of the water.
But most people have little to fear from sharks, and the more people know about them, the easier it is to see that. 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.
So keep the statistics in mind. You aren't going to be bitten by a shark! It's theoretically possible, but so's the chance you'll win 20 million bucks in the lottery. They're both just highly unlikely.
There are always sharks in the ocean. You shouldn't want them gone, as they're necessary. Treat them with respect. Know that you'll swim with them and that's okay. After all, the sea is their home.
https://twitter.com/mims/statuses/747634763528167424
WARNING: Shark in ocean pic.twitter.com/htWjh7qNrU
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