The annual festival of all things Selachimorpha is just a couple of days away. Shark Week kicks off on National Geographic and Disney+ on July 5th.
Shark Beach with Chris Hemsworth kicks off the fun. It follows the global movie star as he embarks on a personal mission to investigate how we can live more harmoniously with sharks.
The one-hour documentary special from Nutopia (“One Strange Rock”) features shark icon and conservationist Valerie Taylor, who takes Hemsworth for a shark dive to experience firsthand the awe and beauty of nurse sharks, and other preeminent shark experts who are exploring new preventative measures and the latest technology to help stave off shark-human encounters.
Charlie Huveneers, a shark expert from Flinders University, shows Chris Hemsworth how electric fields can be used to deter shark attacks. He set aside some time to discuss the technology with SCINQ.
Sharks using electro-reception to track down prey?
Sharks have these amazing abilities to detect electric fields. That’s something that the sharks can use to locate prey that might be buried in the sand or hidden prey. They are able to detect minute amounts of electric field.
The idea of electric deterrence, it’s been around for a while right since about like the 1960s What has gotten in the way of having a consistent and effective device? Why hasn’t one been developed yet?
As you said, the whole idea of using electric field. Back in the 1960s. We’d have textbooks, trying to develop an enclosure to protect a whole area so the initial idea wasn’t as a personal experience. It was more to protect an area. Unfortunately the testing didn’t quite work because of factors such as weather conditions. So as a result, the funding dried out, and they weren’t able to do further testing.
A few years later, researchers started again. They decided to look more into personal deterrence. A company bought or rented the rights to a patent that was developed in South Africa and was able to develop some of this technology and devices further.
I think that the low probability of shark bites is what led to not so many people being interested in what electric field deterrece could do. Because there has been a bit of an increase in the number of shark bites recently, it was reinitiated that interest in personal defense. It also reinforced the need to make sure that this deterrent did work, because there’s a lot of products that rapidly became commercially available without any testing being done.
It doesn’t seem like the whole point of the electric field deterrence is to completely deter sharks. It seems seems like the objective at this point is to make things uncomfortable enough for shark as they go after a bait or something. Do I have that right?
Ideally, you would want to personally completely deter the shark from coming really close. Unfortunately, at the moment, there are no silver bullets, and the only thing we can do is reduce the risk and some of these deterrence concerns. So far, nobody has developed a device that can completely eliminate the risk of shark attacks. Some electric field devices do work and can reduce the risk by 60% which is great already. However, it’s not foolproof and there’s still some risk associated here.
However, what we’re finding through testing is that indeed very strong pulses can stop sharks or make a shark abort a predatory approach towards a potential prey and ideally also towards a humans.
Is there a problem with the electric field and humans? At what level is the electric uncomfortable for a shark? Does the fact that it’s tethered to a human being does that sort of play a role into limits that you can put
That’s a question for either medical doctors or the manufacturers. I think that’s actually where the balance lies in the strength of the electric field. One of the reasons why these two trends are not foolproof is because counter intuitively, the electric field actually dissipates really quickly in seawater. So one thing you could do is to try to increase the strength of the electric field, but then the person wearing it will start probably feeling that pulse. At the moment, you can still sometimes feel the pulse, but it’s not too uncomfortable. It’s not detrimental to humans, but how much can you increase it further without becoming too uncomfortable? It’s basically the big question.
Can you tell me about the device you used in the film? It seems to work decently.
It was a study we did where we tested six different instruments. Some of them were based on magnets, some of them were actually based olfaction — basically using smell to repel sharks. A couple of them useused electric fields. We tested two different electric field source (EFS) devices. It was interesting to see that one of them didn’t really affect the behavior of the shark. The other one did have an effect. It really highlighted how electric fields can reduce risk of shark bites.
Does electric field deterrence work across the board for all sharks or do different sharks have different reactions to that strategy?
We’ve tested some of these electric field instruments on white sharks for sharks and black tip reef sharks and we have seen similar reactions. But you’re right, a shark can have a different sensitivity to electric fields. We’re just about to start some testing on Tiger Sharks as well, to make sure that we can use those deterrents to reduce shark bites not just from white sharks, but also from some of the other potentially dangerous species.