Scientific Study: Effects of the Sharksafe barrier on white shark (Charcharadon carcharias) behavior and its implications for future conservation technologies by Craig P. O’Connell, Sara Andreotti, Michael Rutzen, Michael Meÿer, Conrad A. Matthee, and Pingguo He
Kings of the Ocean
White sharks are one of the most dominant apex predators in the world. They have patrolled deep oceans and coastal shorelines alike since before dinosaurs roamed the earth and are key in maintaining healthy and balanced ocean ecosystems. As people flocked to the oceans, methods were employed to curb shark populations, in an effort to “keep beaches safe”. Mechanisms such as shark nets were implemented at popular beaches, killing not just the targeted sharks but threatened and protected species such as dolphins, turtles, rays and vulnerable shark species such as hammerheads as well. As conservation efforts have grown and shark populations begin their slow recovery, shark sightings have become increasingly common at beaches worldwide. In order for people to enjoy their favorite swimming locations and for shark populations to continue to recover, it is crucial that non-lethal methods of shark deterrents be researched.
Shark Nets in South Africa. These nets are supposed to protect beach goers but ultimately kill hundreds of wildlife like mantas, dolphins, and sharks.
The Search for Peaceful Coexistence
White sharks can be consistently observed at the Dyer Island Nature Reserve due to its large concentration of prey such as seabirds and an estimated 50,000 Cape fur seals. Previous studies indicated that sharks have a natural dislike for electromagnetism as it interferes with their electrical sensors, the Ampullae of Lorenzini. They also rarely enter kelp forests in their habitats even though it is a common refuge for prey species. This study hypothesized that an array of electromagnets in the form of a barrier with the appearance of natural kelp would repel sharks without causing damage to the shark or its sensory organs. The researchers hoped this study would revolutionize the usage of shark repellents at beaches around the world.
The Invisible Wall
The study took place in 2014 at Dyer Island Nature Reserve, in the channel between Dyer Island and Geyser Rock. Over the course of seventy-one at-sea days, the barrier was deployed at a depth of eight meters, and the interactions between the barrier and the native white sharks were observed by two research vessels. The barrier was mounted on a base of concrete blocks and was composed of six regions – two un-manipulated control regions, two procedural control regions designed to look like sea bamboo, and two magnetic regions resembling the procedural control but with the integration of magnets. Each region was composed of PVC and high-density foam to maximize buoyancy.
The Power of Magnets
Over the forty-nine trials, a total of forty-four different white sharks were identified. The data collected from this study showed a strong behavioral distinction between treatment and control types. The control regions were entered by white sharks 256 times, while both the procedural control and magnetic regions were entered an impressive 0 times. To validate the data, the researchers analyzed the data in a second way, and found the magnetic regions yielded the only significant results, meaning the data collected was too strong to be due to chance. The researchers also observed native fish species swimming through the magnetic regions with no change in their behavior, proving the barrier repels white sharks but not other sea life.
Hope for the Future
This study could be key in the future conservation of great white sharks and other large shark species. Because white sharks take so long to reach maturity (males at 10 years old and females between 12-18 years old), and give birth to few young, the killing of great white sharks must be greatly reduced to allow their populations to recover. If this barrier could be implemented at white shark hotspots in place of shark nets and fishing lines, white shark mortality would likely decrease and help the population in its recovery. If current trends continue, white shark populations will continue to decline.
References
O’Connell, Craig & Andreotti, Sara & Rutzen, Michael & Meÿer, Michael & Matthee, Conrad & He, Pingguo. (2014). Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies. Journal of Experimental Marine Biology and Ecology. 460. 37–46. 10.1016/j.jembe.2014.06.004.