The Sharksafe Barrier™ – a cost-effective and environmentally friendly alternative to conventional anti-shark devices developed by researchers from Stellenbosch University (SU) and the University of Massachusetts Dartmouth – is one of the technologies that will compete for potential investment in the 'Pitching Den' during the SA Innovation Summit taking place in Cape Town this week.
The competition is part of the Global Cleantech Innovation Programme (GCIP-SA) – an international initiative that aims to address the most pressing energy, environmental and economic challenges of our time through promoting clean and innovative new technologies.
Dr Sara Andreotti, a marine biologist in SU's Department of Botany and Zoology, will be doing the pitching. She developed the Sharksafe Barrier™ in collaboration with Dr Craig O' Connell (University of Massachusetts Dartmouth), Michael Rutzen (white shark conservationist and shark cage diving operator) and Prof Conrad Matthee (head of the Department of Botany and Zoology at SU).
This innovative structure is composed of an array of black plastic pipes deployed in the ocean, to biomimic a kelp forest when viewed from within the water. The pipes are anchored to the sea-floor and are vertically buoyant.
“Our work indicates that kelp forests deter large predatory sharks and that they generally avoid swimming through them," explains Dr Andreotti.
Furthermore, to enhance the effectiveness of the barrier, ceramic magnets are arranged along the length of the artificial kelp forest. Previous work showed that magnets deter shark species, including great white sharks, bull sharks, tiger sharks and hammerhead sharks.
The concept has been tested in Gansbaai, the mecca of South Africa's great white sharks. The research team built an underwater exclusion zone of 13 x 13 metres, and attracted sharks to the middle using bait. After 34 trials, and with 255 hours of video footage collected over two years, not a single white shark entered the zone. Smaller fish, like skates, herring and mallets, did enter the exclusion zone and moved freely between the kelp-like structures.
The results from this project was published in the journal Aquatic Conservation: Marine and Freshwater Ecosystems recently, with the title “Testing the exclusion capabilities and durability of the Sharksafe Barrier™ to determine its viability as an eco-friendly alternative to current shark culling methodologies".
The Sharksafe Barrier™ concept has been patented by SU, and has been accepted in Australia (2013350811) and Europe (13821175.0), with applications pending in Brazil (BR112015012008-3), the USA (14/647,646) and South Africa (2015/04471). (F2016/00959; F2016/00960; F2016/00961; F2016/00962). The Shark Barrier End
Caps concept (F2016/00959;
F2016/00960; F2016/00961; F2016/00962) has been granted as a functional design
in South Africa.
Dr Andreotti says the technology addresses two major issues: the unjustified loss of human lives and the equally unjustified loss of marine life (whales, turtles, dolphins and sharks) due to the use of shark nets and drumlines: “Between 2011 and 2016 there have been 491 registered shark attacks worldwide, of which 43 proved to be fatal. Over the past 20 years, however, almost 4 000 sea creatures have been caught in shark nets lining the beaches of New South Wales in Australia alone."
Tourism is another important reason for protecting the world's great whites. In South Africa, the local white shark diving tourism industry is worth US$4.4 million a year: “The temporary disappearance of white sharks in 2017 has already forced one of the eight cage diving companies to suspend their activities" she warns.
The popular tourist destination, La Réunion Island, experiences on average a 40% loss in bookings after a shark attack. Between 2011 and 2016, there have been 19 shark attacks in this area, forcing the authorities to permanently close one of the beaches, she adds.
As part of the Global Cleantech programme, the public is invited to participate in an opinion survey about beach safety and people's perceptions about sharks and shark conservation. Click here to participate.
Photos: Daniel Botelho