Testing a Shark Deterrent | Shark Beach with Chris Hemsworth
I think it's fair to say, however good we get at keeping humans and sharks apart in the ocean, there will always be moments when we meet. In those worst-case scenarios when sharks bite, is there anything that can be done?
Charlie Houveneers is a scientist who's thought more about this than most.
“Hey mate, how are you?”
For several years, he's been looking at ways of deterring sharks that decide to attack.
“Is your, uh, research and line of work due to your passion and love for sharks or passion and love for humans? Or who are you more invested in? It's okay to say the sharks too.”
“You do things in my situations, but yeah, it's a combination. It's really, I've always been interested in sharks since I'm a kid. Yeah, and yeah, the fascination for sharks just changing to a real interest in the science and understanding the sharks better so that we can actually help and provide a safer environment for people but also for sharks.”
“Yeah, are you going into the field soon to test any of those deterrents?”
“Yeah, actually, we're going next week.”
“Well, good luck with it.”
Thanks. Charlie and his colleagues from Flinders University in Adelaide are heading into the seas off South Australia. On board, they're testing the latest shark deterrent and protection technologies.
“So what we've seen is that in the recent years, there has been an increase in the number of sharks globally, including in Australia. This has resulted in a lot of interest in the devices to try to reduce those risks.”
The team have sailed to the Neptune Islands, a hot spot for great whites. The sharks come here to prey on Australia’s largest colony of long-nosed fur seals, so it's the perfect place to test products designed to take advantage of sharks' very unusual senses.
“There’s only a small number of animals that have this ability to detect electric fields, and sharks have it through these black dots called ampullae of Lorenzini. The idea behind these electric field-based deterrents is that they will produce such a strong pulse that it will overwhelm the sensory organ and make the shark basically move away from the source."
The aim is to develop a safer surfboard with an electrical shark deterrent built into it.
“This produces an electric field through two electrodes which are positioned just underneath the board, and this is kind of a replica of a surfboard. This produces a field which is transmitted to this electrode and creates a bit of a barrier around the surfboard, which in theory should be deterring the sharks.”
To test the theory, the experiment compares a shark's reactions to a board with the electrical device switched on to a board with it off. But getting robust data means repeating the process many times over.
Over hundreds of previous trials, the team have captured remarkable footage of sharks in action. First, they recorded what happened to a baited board with a device turned off.
“It’s interesting that we do have a bait just underneath that board swimming as we would expect to see it swimming around a bait. And then what happened to the sharks when the device was turned on.” [Music]
“So that was a pretty obvious flinch. He's coming back now. That kind of flinching reaction we didn't see that when the deterrent was turned off, and you can see the really obvious flinching in the gills as well in the jaw gaping. Well, look at that one. So that one came really from down below; it was only within half a meter.”
Overall, there was a 60% reduction in the proportion of weight being taken.
“60% reduction in shark bites. If the eight people killed by sharks in Australia in 2020 had been able to use an electric deterrent like this, then five may still be alive.” [Music]
Products like these are promising, as we may be able to reduce fatalities in the future, all without harming the sharks.