SA’ners’ technology used for sharks in the Bahamas


The SharkSafe BarrierTM, which was developed 15 years ago in the Western Cape by marine biologists from Stellenbosch University (SU), was installed a few months ago at a private island in the Bahamas.

This is the first commercial installation of the SharkSafe BarrierTM and the breakthrough that the South African team of developers has been working towards for the past 15 years.

“We now have the technology to allow the rightful inhabitants of the oceans to survive and thrive, and for environmentally conscious people to be safe while enjoying the ocean,” says Dr. Sara Andreotti, a marine biologist at SU and co-founder of the SharkSafe BarrierTM.

This nature-inspired technology – which was installed at the Berry Islands in August – combines biomimicry of a seaweed forest with magnetic fields to keep people and sharks away from each other, without harming the sharks or any other large marine species in the process.

It is also currently the only eco-friendly alternative to shark nets, which cause the death of thousands of sharks and other marine species every year.

The thinking behind the development of the SharkSafe BarrierTM concept is a combination of practical experience with sharks, and understanding their behavior from the perspective of a marine biologist, Andreotti now explains.

Andreotti says that this technology has undergone rigorous testing since 2012 in the stormy sea waters on the South African coast, but also on the sandy beaches of Réunion and the Bahamas. The results of several of these case studies have since been published in accredited academic journals.

Among other things, it has been observed that fish and other marine animals such as seals use seaweed forests as a hiding place from predatory sharks. “By imitating a natural seaweed forest, created by overlapping rows of plastic pipes anchored to the seabed, it has been proven that the SharkSafe BarrierTM is an effective deterrent for predatory sharks,” says Andreotti.

Marine biologists also know that most shark species are sensitive to strong magnetic fields due to the presence of electromagnetic receptors on the tip of their heads. These small vesicles and pores – called ampullae of Lorenzini – are directly connected to the shark’s brain and enable them to sense the transmission of faint bioelectric impulses in the water, caused by their prey.

The developers of the SharkSafe BarrierTM therefore created a strong magnetic field by placing magnets inside these seaweed-like pipes. “But instead of attracting the attention of the sharks, this excessively strong magnetic field overstimulates the ampullae of Lorenzini and therefore serves as another deterrent,” explains Andreotti.

SharkSafe BarrierTM today consists of high density polyethylene pipes manufactured locally by KND Fabrications in Maitland. During installation, these floating pipes are anchored in the sea, one meter apart, on a grid-like structure.

Large ceramic magnets are placed at different heights in the row facing the open ocean. The structure is then weighed down on the bottom with cement blocks of 200 kg each which are fixed with anchors in the stone and sand.

The cement blocks are also shaped like stone clams in order to withstand the onslaught of waves and swells.

In addition to combining two proven shark-specific deterrent strategies, the SharkSafe BarrierTM is also designed to remain in the water for at least 20 years with minimal maintenance requirements. This offers marine life an opportunity to make themselves at home on the cement blocks that anchor the barrier to the seabed, thus forming an artificial reef.

Andreotti says the installation of the SharkSafe BarrierTM in the Bahamas is a win-win situation, especially for the areas that rely on ocean-related activities as their main source of income, such as coastal towns in South Africa, Brazil, New Caledonia, the Bahamas and Reunion.

Shark tourism currently contributes approximately US$100 million per year to the Bahamas economy.