In the story of an epic journey across the Pacific Ocean, one particular character might quickly come to mind. Ben saw it first, actually; it was just
straight on the bow of the boat three meters away – it was, like, bigger than Ben. Before we left, we finally managed to
get in touch with a shark specialist to ask what to do in case of sharks. That specialist was Dr. Charlie Huveneers, a biologist who works to unlock
the mysteries of shark behavior. Charlie and his team hope to find scientifically sound ways to help sharks and humans share the ocean. There’s a lot of situations when sharks and humans
will be interacting, will be in the same area without anything happening. Overall, some of these pelagic species
are typically quite curious. Evolutionarily, if you’re living in the middle of the ocean, you’d need to be curious and investigate random objects to be able to survive. Unfortunately, it’s hard to be in the mind of a shark to be able to understand why in some cases sharks do decide to attack. In the case of Ben, like any other human, the risks overall from shark attacks are very, very low. However, Ben will be spending a fair amount of time in the water, swimming in a fairly remote location where white sharks are more likely to be occurring. Sharks have a fearsome reputation.
But only a handful of the hundreds of known species could pose a threat to humans. Nonetheless, the crew consulted with Charlie on their options to lower Ben’s risk of a dangerous encounter. A deterrent is effective when it can
reduce the risk of a shark bite. There are things like chemical repellents aimed at overwhelming the olfaction, the smell of the shark; there are wetsuits that are trying to somewhat camouflage the person wearing it; there’s no silver bullet. It turns out that the same super sensory adaptations that have allowed these prehistoric predators to flourish in every ocean for 400 million years… may also be the key to how we can coexist with them today. The electromagnetic sense that sharks have is called the ampullae of Lorenzini. It is small pores that are located on the snout of the sharks, that are filled with a gel. That gel is conductive, and allows that electric field
to be passed on to the sensory organs and then processed by the brain. And that enables them to feel and detect a very weak electromagnetic field in the water. So if sharks use these heightened senses to detect prey, can we design technology that can tap into the sharks’ electromagnetic receptors,
to keep both humans and sharks safe? To find out, Charlie and his team placed five different deterrents in known shark hangouts and attempted to lure the sharks
towards some tasty tuna. Two were based on electric fields. We had a total of 300 trials. During those trials,
we tested about 44 sharks, interacting with our experimental gear,
and these sharks did more than 1500 passes. What the team found was that only one of the deterrents tested had any effect on the behavior of the sharks: the Shark Shield, that targeted the sensitive ampullae. When you have the shark shield,
it is very annoying for sharks. So at first they are curious and they come close,
but if they come too close it’s a bit like a very loud speaker for your ear.
You won’t stay around. It doesn’t harm you, but it’s a bit annoying. Without any deterrent, the shark was taking the bait that we were presenting them about about 96% of the time. Once we used this electric field deterrent, the proportion of bait being taken by the shark
was reduced down to 40%. The crew keeps this device aboard the dinghy
while Ben swims, but Ben didn’t need it during his recent peaceful encounter with a mako shark. But it seems such a moment with a shark that isn’t a man-eating machine is still quite difficult for some to imagine. Some studies have suggested that the public tends to overestimate the occurrence of shark attacks by 10 or even 100 times. There’s just so little we actually know
about these fascinating fish. We’ve got more than 500 different species of sharks and out of those there are still a lot of species that are currently unknown. We don’t even know their reproductive cycle. We don’t even know where they’ve been feeding. The reason why I stay in the water whenever we have any type of sea life is to observe it and try to understand it a little bit more. It’s not about Jaws, the movie that we all know. Sharks are not like that. Sometimes they are like us, or like any animals;
they are curious. When people mostly first dive with sharks, the first thing they say is “wow, that was impressive. That was beautiful.” They’re more in awe rather than they were in fear. Ben’s swim across the Pacific is amazing. Obviously, you know, he has to be careful But in most cases, he’ll be quite lucky to be able to observe these animals in a natural environment that not many people get to see as well. Be sure to visit Seeker.com/theswim to
read daily updates from Ben Lecomte, track his progress in real-time, and watch more videos about the science happening onboard Seeker. Click here for this next episode, and don’t forget to subscribe. Thanks for watching!