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Meet the startup using magnets to keep sharks at bay

© Rodolphe Holler

Editor’s note: Around the world, innovative businesses are helping to solve some of the biggest environmental challenges of our time. Conservation International’s investment fund, CI Ventures, provides funding and support for early-stage companies that are generating positive impacts for people and nature. In this occasional feature, we highlight their work. 


In popular culture, sharks are often portrayed as terrorizing innocent beachgoers. But in reality, they have far more to fear from humans than the other way around. Sharks rarely attack people — but they are the target of intense overfishing, with an estimated 100 million sharks killed every year. 

Yet myths endure. And to protect beachgoers, governments often resort to ineffective strategies like shark nets, which don’t ward off sharks, but can be deadly for turtles and dolphins that get tangled in them.

Now, a new company in South Africa is offering an alternative.

SharkSafe Barriers, a CI Ventures investee, is pioneering a better way to protect surfers and swimmers, without further depleting shark populations or hurting other marine wildlife.

Conservation News sat down with Sara Andreotti, a marine biologist and chief operating officer of SharkSafe Barriers, and Gracie White, who leads CI Ventures’ ocean investments, to learn more.

Sharks are slow breeders and the target of intense overfishing — a recipe for extinction. © Shawn Heinrichs

Conservation News: Paint the picture for me — why is shark conservation so fraught?

Sara Andreotti: Let’s start with the shark’s perspective. The earliest evidence of sharks goes back 450 million years — that makes them older than trees and dinosaurs, and survivors of five mass extinctions. Yet, in just 50 years, shark and ray populations have dropped 71 percent, mainly because of overfishing. That’s bad news for sharks, but also for ocean ecosystems where these apex predators keep marine food webs in balance.

At the same time, like other large predators, sharks inspire a sort of primal fear in people, despite the fact that you are far more likely to be killed by a lightning strike than a shark. But we can’t talk about shark conservation if people are traumatized. If they are afraid, they don’t want to hear about how critical it is to protect these magnificent creatures, they just want to get rid of the problem.

Gracie White: There’s another concern. While some people fear sharks, others are fascinated by them. Shark tourism has grown into an economic powerhouse, generating more than US$ 300 million every year and supporting thousands of jobs in coastal towns — from the Bahamas to South Africa to the Galápagos Islands. If sharks disappear, so would many communities' income streams. Yet at the same time, shark attacks can scare tourists away. For example, on Réunion Island in the Indian Ocean, a spate of shark attacks over the last decade has been connected to a 13 percent drop in tourism to coastal towns. It’s a real issue that so far has been difficult to solve.

Sharks date back 450 million years, making them older than trees and dinosaurs. © Shawn Heinrichs

It seems like I hear about shark attacks on the news a lot — are they on the rise?

GW: The number of shark attacks has remained consistent over the years; they are still exceedingly rare.

However, the potential for interactions between sharks and people could be on the rise. Why? There are more people in the water surfing, swimming and scuba diving. Moreover, studies show that warming ocean temps are pushing sharks north into cooler, and more populated, waters. And humans are disrupting their breeding and hunting grounds.

Take Recife, Brazil. Before the 1990s, there were no reported shark attacks. Then, between 1992 and 2012, 56 attacks occurred in the city’s waters. What changed? No one knows for sure, but a large port was built in bull shark breeding and hunting habitat, potentially driving the sharks closer to Recife’s beaches. At the same time, trash discarded from the ships, and the low frequency sounds they emit, may have also attracted sharks. The city’s beaches are lined with signs warning of the risk of shark attacks, and there’s a strict ban on surfing — a real shame for a city that was once a destination surf spot. As we spend more time in the water and encroach on shark habitats and food sources, we have to find ways to coexist.

How do governments try to prevent attacks?

SA: Governments rely on a variety of methods to try to protect beachgoers — from deploying lifeguards and drones, to catching them with baited hooks known as drumlines. We are most concerned about shark nets, which are intended to reduce the number of sharks, but are highly ineffective, as sharks can swim under, over and around them. Plus, shark nets can have tragic effects on marine life. One study found that more than 60 percent of wildlife caught in the nets — including threatened turtles, dolphins, whales and manta rays — died. Not to mention that Great White, bull and tiger sharks are all threatened, so governments — which typically install the nets — are effectively culling species that are in serious decline.

And this is where SharkSafe Barriers can help? 

SA: Yes. As the name implies, it’s a safer alternative to shark nets — for both sharks and people. It uses two methods to deter sharks from entering beaches: First, it mimics a thick kelp forest — which sharks naturally tend to avoid — using flexible pipes that flow in the waves like a kelp forest would. Then, inside those pipes, are magnets. Sharks rely on electromagnetic receptors at the tip of their heads to navigate and hunt prey. The powerful magnets in the pipes overwhelm them, causing a sensation similar to someone shining a bright flashlight directly into your eyes. We’ve done many tests off the coasts of South Africa, the Bahamas and Réunion Island, tempting the sharks with food on the other side of the barrier. Not once have they crossed the barrier. Yet, other marine animals such as fish, manatees and turtles can cross it freely without getting entangled.

SharkSafe Barriers mimics a kelp forest and uses powerful magnets to deter sharks. Courtesy of Andreotti

That sounds like a win-win. What’s getting in the way of moving to market?

SA: In one word: cost. Upfront, it’s more expensive to install our barriers than nets. However, these barriers will last for at least 20 years with minimum maintenance, making them far cheaper than nets in the long run. In addition to cost, SharkSafe Barriers is a relatively new technology. Shark nets, on the other hand, have been around for almost 100 years — and despite their issues, people and governments are accustomed to them. Changing established systems is always difficult.

During multiple tests, sharks have never crossed the barrier. © Daniel Botelho 

How is CI Ventures helping overcome these hurdles?

GW: Each barrier is custom built for the beach it will protect. Even before a sale is made, SharkSafe Barriers representatives need to visit the site and dive to take measurements of the area so they can make a plan for the installation. That can be expensive. CI Ventures is providing a loan and a flexible line of credit to help SharkSafe Barriers get into the market. 

What’s next for SharkSafe Barriers?

SA: We recently installed our first commercial barrier on an island in the Bahamas. It’s incredibly exciting to reach this point — I’m hopeful this will give us the momentum we need to grow and prove that sharks and humans can coexist peacefully. It’s been a long road to get here. We first developed the idea 15 years ago and it’s immensely satisfying to finally see it come to fruition. But there’s still much work to be done and we must keep at it. Sharks are slow breeders, which puts them at a higher risk for extinction. And, there’s still so much we don’t know about them.

Our biggest challenge is getting people to see these magnificent creatures differently and understand how important they are to the ocean. Our hope is that by making people feel safe, we can inspire them to want to protect it, and all its creatures.

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Mary Kate McCoy is a staff writer at Conservation International. Want to read more stories like this? Sign up for email updates. Also, please consider supporting our critical work.