Not only are sharks strikingly beautiful, but without sharks patrolling the seas marine ecosystems would be thrown entirely off balance. Sharks weed out weak and sickly prey, keeping other species fit. Additionally, sharks keep the ocean healthy by feeding on prey species, ensuring that they don’t become overabundant. In essence, the shark is one of evolutions most impressive success stories.
Yet, sharks are feared and in some cases ostracised. For many, the great white shark is considered a dangerous predator with a penchant for human flesh – films like Jaws and Open Water have simply perpetuated this gross misjudgement. Going shark cage diving is one of the best ways to dispel misconceptions for yourself, but due to a somewhat crippling public fear of shark attacks, preventative measures such as shark nets have become the norm in coastal areas.
As an apex predator, the great white shark has been a protected species since 2005 under the Convention on International Trade in Endangered Species (CITES, Appendix II) and the Convention for Migratory Species (CMS); furthermore, due to rapid population declines, the species is listed as vulnerable to extinction according to the International Union for the Conservation of Nature (IUCN, Category VU A1cd+2cd; Dulvy et al. 2008)
While protecting swimmers from potential shark attacks, shark nets actively injure sharks and have led to the strangulation and suffocation of all kinds of sea animals. As traditional shark nets have unquestionably caused more harm than good, an eco-friendly shark barrier called Sharksafe which will not only shield swimmers, but protect marine life too, has been developed.
The project is the result of a huge collaborative effort between the PhD candidate Craig O’Connell from the University of Massachusetts Dartmouth, Dr. Conrad Matthee and Sara Andreotti from Stellenbosch University, and Mike Rutzen of Shark Diving Unlimited. The team have been developing the Sharksafe Barrier since 2011, each contributing their areas of expertise and, in some instances, funding.
The Sharksafe Barrier is constructed from rigid pipes that emit a magnetic barrier which, when erected on the seabed, resemble seaweed. These features are effective in two ways: sharks are sensitive to magnetic fields and it will deter them from attempting to swim through the barrier, and great whites seem to particularly detest kelp and tend to avoid it – an observation made by Rutzen, who has an intimate understanding of great white behaviour.
The Sharksafe Barrier’s deployment cost which amounts to R10 000 000, is built to sustain functionality for over 10 years while withstanding up to seven metre swells and requiring a maximum of one check-up per year. Therefore, besides being environmentally friendly and long-lasting, the associated manual labour once the barrier is deployed will be minimal .
Under the guiding eye of Rutzen et al. the Sharksafe barriers have been exclusively erected at Dyer Island in Gansbaai by Shark Diving Unlimited vessels, who also offer shark cage diving. Stellenbosch University has patented the system. In the long run, it is hoped that this new alternative to shark nets may actively reduce the number of related marine life deaths and curb the few shark attacks which actually occur.