The Future Of The SharkSafe Barrier™ Doesn’t Look Too Bright

After a long day of fishing, sometimes you don’t want to take the mess back home with you. Instead, cleaning up the fish right at the dock sounds mighty appealing… both for a fisher and for what lurks below waiting to snap up the scraps.

One of those predators taking advantage of this sort of food provisioning is the bull shark (Carcharhinus leucas), a large coastal shark species found in shallow subtropical and tropical marine ecosystems. Known for their ability to tolerate a wide range of salinities, and have been responsible for non-fatal and fatal encounters with humans. In an attempt to maximize the safety of beachgoers, bull sharks are often targeted by local governments through invasive culling measures such as beach nets and drumlines… which is bad news for a species that doesn’t reach sexual maturity until their late teens, is slow-growing, and typically produces a litter size that ranges from one to 13 pups. Due to this, the ‘fearsome’ bull shark has been listed as being “Near Threatened” on the International Union of the Conservation of Nature (IUCN) Red List.

Enter the SharkSafe Barrier™. Initially developed by Dr. Craig Patrick O’Connell over the last 15 years, the Founder and Executive Director of O’Seas Conservation Foundation, Inc. and his team continued his research to further determine if this technology could be reliably used as an eco-friendly alternative to current shark culling methodologies (e.g. shark nets and drumlines). “In previous years, we’ve seen this technology successfully exclude motivated bull and white sharks from bait; however, there had been zero attempts at a larger scale shoreline deployment due to funding constraints,” explained the Discovery Channel presenter and lead author of the study. “The goal was to achieve this type of deployment to determine how the smaller-scale experimental results would translate.”

The bull sharks in Bimini proved to be a perfect candidate for his experiment. The researchers headed to the Bahamas, focusing on a spot that was adjacent to a food-provisioning site for bull sharks. As the sharks entered the area to check out if there was a chance for an easy meal, the individuals were identified through unique characteristics such as size, sex, presence or absence of a tag, colour, presence or absence of fin damage, and presence or absence of scars. GoPros recorded the shark’s behavior as they swam in the three experimental sections: two control regions on either side of the one SharkSafe Barrier™ area. Each trial period would last an hour; during this time, equal amount of chum was placed within the experimental region and the designated control region and one Mako Magnet was introduced to the centre of each region to create a low-frequency intermittent pulse that served as an additional auditory stimulus to attract sharks. Statistical analysis based on 59 trials illustrated that the bull shark’s swimming behaviour (i.e. avoidances, entrances, and pass arounds) significantly differed between the control (i.e. unmanipulated area) and the experimental (i.e. SharkSafe Barrier™) regions. Unlike previous small-scale experiments, 10 of 16 sharks repeatedly penetrated the barrier and swam in an accelerated manner once within the experimental barrier region.

The results were surprising to the scientists. “Although previous small-scale deployments resulted in a highly effective barrier that could exclude bull sharks from bait, this large-scale deployment revealed a much more ineffective technology. It was a disappointing result since 1) I’ve spent so much time developing and studying the technology and 2) so many people were hopeful that this would be a successful alternative to shark culling approaches,” he lamented. “However, we learned tremendously from the study and developed a novel barrier, known as the Exclusion Barrier. We will have a peer-reviewed publication coming out shortly – but the new system is exciting and may have a future for shark and beachgoer protection.”

“Shark safe” or “shark deterrent” technology can be quite polarizing. Many have reviewed the evidence behind popular electrical, magnetic, acoustic, and other kind of products… but the jury is still out with only a few being scientifically proven to work (on some species, not all). O’Connell is one of the scientists who does not believe this sort of technology has a future, although he is proud how far the SharkSafe Barrier™ has come and believes it helped contribute to awareness within the general public pertaining to the negative impacts associated with current shark mitigation measures. “Our scientific findings reveal a major flaw in the technology that will inevitably result in continuous shark penetration through the barrier with time. This has not only been observed with bull sharks but on two occasions on white sharks in Gansbaai, South Africa as well. [But] in science even our failures are successes. We can use the data collected from this study and learn from it and use it to advance our field. ”

Should the Exclusion Barrier technology continue to exhibit success, O’Connell and his nonprofit organization have committed to raising funding to support the barrier’s material and deployment costs. “In the past, local municipalities have continually expressed their lack of interest in the SharkSafe Barrier and other less-invasive shark mitigation technologies due to their inherent costs and that is why my organization has learned and made this new technology even more accessible,” he said. “We don’t want the price of an eco-friendly technology to be a hindrance to stopping the barbaric practice of shark culling. So should we continue to have promising results, we hope that this barrier may help make shark culling a thing of the past. But…only time and experimentation will tell.”