Proudly South African SharkSafe Barriers installed in the Bahamas.

November 13, 2023

“Swim on, sharks, nothing to see here”, quipped The Guardian newspaper mid-July 2020, in an article that questioned whether the so-called ‘fake kelp’ designed by a South African marine biologist could prevent shark attacks. At that time, while the hot-button topic of shark cull was being debated worldwide, a remarkable conservation team from Stellenbosch University, led by Dr Sara Andreotti, and supported by Italtile’s SharkWise Project, were literally up to their necks in turbulent seawater off the coasts of South Africa. They had been developing, testing and refining unique, biomimetic technology called the SharkSafe Barrier, designed to create safe waters for sharks and humans.

Dr Sara Andreotti’s SharkSafe Barrier is designed to behave like a kelp forest – which sharks dislike – with rods that contain ceramic magnets. This ‘fake kelp’ works to scramble shark ‘hunting radar’ and repels sharks away from the barrier of rods. At the time of The Guardian’s article, the team had installed test barriers off the coast of Réunion, which up to then had been protected by shark nets (safe for humans but a cruel death sentence for endangered shark populations). 

Cut to August 2023, when a permanent 30 metre SharkSafe Barrier was installed in the cays around the Berry Islands – a chain of eco-conscious islands in the Bahamas. This is a victory for the team, and a magnificent tribute to their dedication, passion and persistence. Read all about it below.

The eco-friendly SharkSafe BarrierTM technology, developed by marine biologists at Stellenbosch University (SU) and their collaborators, and manufactured in the Western Cape, South Africa, has now been installed at a private island in the Bahamas.

The SharkSafe BarrierTM combines biomimicry of a kelp forest and magnetic fields to keep humans and sharks apart from each other without harming the sharks or large marine species. According to Dr Sara Andreotti, marine biologist at SU and co-founder of SharkSafe BarrierTM, this nature-inspired technology is currently the only eco-friendly alternative to shark nets, which result in the death of thousands of sharks and other marine life every year.

The installation of a 30-metre long SharkSafe Barrier at the Berry Islands in August this year will further strengthen marine conservation efforts in the Bahamas. In 2011 the Bahamas proclaimed the first shark sanctuary in the Atlantic Ocean, and, in 2018, a Marine Action Partnership (MAP) for Sustainable Fisheries. Shark tourism currently contributes approximately US$100 million per year to the local economy.

More about the technology

Andreotti says since 2012 the technology has undergone rigorous testing in the turbulent ocean waters along the South African coast, as well as in the tropical waters of Réunion island and the Bahamas. The results from several of these case studies have been published in peer reviewed scientific journals.

The thinking behind the development of the SharkSafe BarrierTM concept is a combination of practical experience with sharks and marine biologists' understanding of their behaviour, she explains.

Firstly, fish and other marine animals such as seals have been observed to use kelp forests as a hiding place from predatory sharks. By bio-mimicking a natural kelp forest, created by overlapping rows of plastic pipes anchored to the seabed, the SharkSafe BarrierTM has proven to be an effective deterrent for predatory sharks.

Secondly, marine biologists know that most shark species are sensitive to strong permanent magnetic fields because of the presence of electro-magnetic receptors at the tip of their heads. These small gel-filled pores – called 'Ampullae of Lorenzini' – are connected directly to sharks' brains and allows them to register faint bioelectrical impulses dispersed in the water from their prey.

Using this knowledge, the developers of the SharkSafe BarrierTM created a strong magnetic field by inserting magnets into the kelp-like pipes. But instead of attracting the attention of a shark, the overly strong magnetic field over-stimulates the Ampullae of Lorenzini and therefore acts as another repellent. In other words, by inserting strong magnets into the kelp-like pipes of the barrier, it further strengthens the ability of the design to repel sharks, Andreotti explains.

Today, the SharkSafe BarrierTM consists of high-density polyethylene pipes manufactured locally by KND Fabrications in Maitland, Cape Town. During installation in the ocean, the buoyant pipes are anchored on a grid-like structure one metre apart from one another, with large ceramic magnets staggered in the ocean-facing row. The grid is then weighted by limpet-shaped 200-kilogram cement blocks and secured by rock anchors and sand. 

Apart from the fact that the SharkSafe BarrierrTM combines two proven shark repellent strategies, it has also been designed to remain in the water for at least 20 years with minimal maintenance required. This offers an opportunity for marine life to settle on the cement blocks which anchor the barriers to the seabed, forming an artificial reef.

Revolutionising the concept of shark management

For Andreotti, the first commercial installation of the SharkSafe BarrierTM is the breakthrough that the team 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 sea-loving humans to enjoy their time in the water safely," she says.

This is a win-win situation, especially for areas that rely on ocean recreation as a main source of revenue, such as beach towns in South Africa, Brazil, New Caledonia, the Bahamas and Réunion, she concludes.

Author: Wiida Basson (Media: Faculty of Science)

Italtile’s SharkWise Project and you. We first encountered marine biologist Dr Sara Andreotti back in 2021, and after we learned about her life’s work to foster harmony between sharks and humans, we were inspired to support her mission.

Italtile’s SharkWise Project was founded, in partnership with ITD and Tivoli Taps, which enables our customers to play their part in shark conservation: Italtile donates R2 of every Tivoli tap purchase to shark conservation. We are very proud of our R2-per-tap initiative, which raised R 150 000 in 2022 to fund Sara and her team.

Read more about their extraordinary work here.


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