Between 1950 and 2008 about 577 great white sharks and 352 tiger sharks were caught in shark control nets off NSW’s coastline. In addition more than 15,100 other marine animals were caught and killed in nets during this same period including turtles, whales, dolphins, rays, dugongs, and other species of sharks. The Great White Shark is currently listed as a vulnerable species in Australian waters and mortality from accidental or illegal (i.e. targeted) capture by fishers, and shark control activities are listed as the principal threats and likely contributors to the lack of white shark recovery in Australia. But how do we reduce harmful interactions between people and sharks?
With the support of a Taronga Field Conservation Grant an initiative known as the ‘Sharksafe Barrier’, is being trialed in ‘Shark Alley’, Gansbaai, South Africa. The shark deterrent technology aims to prevent negative interactions between sharks and humans, and reduce the impact of shark nets and baited drum lines on sharks and other marine animals. While the study focuses on White sharks (listed as vulnerable by the IUCN), the technology will have positive impacts on the entire marine ecosystem. The eco-friendly shark barrier successfully bio-mimics the visual effects of Kelp forests and utilizes a series of permanent barium-ferrite magnets to form a repelling magnetic barrier to sharks. Barrier circles have been baited to actively attract sharks, and to date, have been 100% successful in preventing sharks entering the barrier (18 samples). Seals and bony fishes remain unharmed by the barrier and are able to cross the magnetic field to swim among the ‘kelp’.
The Sharksafe Barrier team was able to complete their field research thanks to the Conservation Grant. The focus will be to assess exclusion capability and whether White sharks become habituated to the barrier. The team is also testing the durability and strength of the barrier structure and its ability to be deployed on a variety of substrates and under different environmental conditions. As the sharks start coming to Shark Alley in June, the researchers are busy setting up cameras to record the sharks’ behaviour. Watch this space for more updates later in the year!
You can also check footage from the 2015 field season by clicking here!
Story by conservation champions Jane Hall, Phoebe Meagher and Tarryn Williams