11:32am Nov 28, 2017
A team of South African scientists claim to have designed an eco-friendly shark barrier that is 100 percent safe and, unlike other net systems, promises to protect surfers from deadly attacks.
The Sharksafe Barrier copies Mother Nature and was developed after marine biologists observed seals in South Africa swimming into forests of kelp to avoid being killed by great white sharks.
Time and again, on approaching the kelp, the fearsome great white sharks would turn away and refuse to enter these areas, according to Dr Sara Andreotti, one of the founders of Sharksafe Barrier.
The design of the shark barrier, which is made up of a series of dark coloured floating pipes anchored vertically to the ocean floor, mimics the appearance of kelp forests.
Not a single great white or other shark had breached their barrier in six years of testing, Andreotti told Nine.com.au.
By employing technology that does away with traditional mesh netting, there is no “by-catch” with Sharksafe, the term used to describe the killing of other sea life by shark nets.
It is impossible for sharks, dolphins, turtles or other sea creatures to get caught and die in the barrier, Andreotti said.
The system can also be deployed in much deeper water than regular shark nets, allowing it to be positioned behind surfers.
Shark nets in NSW are generally set in water depths of 10 metres. But Andreotti said their shark barrier can be installed along any length of beach, and in depths of ocean up to 20m.
The barrier, which is under observation by the NSW Department of Primary Industries (NSW DPI), also employs the use of magnets to deter various shark species.
“We have tested Sharksafe with all the major species of sharks considered dangerous to humans, including great white sharks,” Andreotti said.
“I can say very confidently the barrier is 100 percent safe and effective.”
During testing, Andreotti and her team used chum, a fishing term to describe ground up blood and fish guts, to lure “highly motivated” sharks to try and penetrate the barrier.
Phase one of testing saw chum placed behind a single 50 metre wall of the barrier in the ominously named and famous Shark Alley of Gansbaai, in South Africa’s Western Cape.
Great whites, bull sharks, tiger sharks and hammerhead sharks all swam along the entire length of the wall and around the ends to reach the food source.
During the next stage of testing, which lasted several years, the Sharksafe team built a 15x15m square wall and placed chum inside the secured perimeter.
Again, not a single shark breached the barrier, according to Andreotti.
Marine biologist Andreotti said it was impossible to know for certain why great whites showed such an aversion to the kelp, but they had several hypotheses.
She said great whites probably had an in-built instinct to avoid getting trapped.
“They have to be swimming all the time to oxygenate their gills,” Andreotti said.
“If they get caught in thick kelp it is going to be difficult for them to reverse.”
Lack of visibility in thick kelp forests also created a poor hunting environment for the apex predators, Andreotti said.
Following five years of tests in South Africa and the Bahamas, Andreotti said Sharksafe now has its sights set on installing the system on New South Wales beaches.
“We think Australia is where there is the biggest demand for an eco-friendly alternative shark net.”
Almost 4000 sea creatures have been caught in shark nets lining NSW beaches over the past 20 years, Andreotti said.
Of the 3944 marine animals trapped, Andreotti said 40 percent were not sharks – and less than 4 percent were considered harmful to humans (100 white sharks and 49 tiger sharks).
The NSW government was watching to see if the technology had progressed to a stage that meant it was ready for testing off NSW beaches, the spokesperson added.
“NSW DPI continues to monitor this technology and its suitability for tolerating sand movement and the dynamic ocean conditions of NSW beaches.”
The barrier was robust and had been tested in massive seas off The Cape of Good Hope, Andreotti said. Although extensively tested, the Sharksafe Barrier has yet to be set as an operational defence system protecting humans on a beach.
In good news for surfers, Andreotti was adamant that Sharksafe has no negative impact on surf conditions, as waves and wave energy passes right through the floating barrier system.
NSW surfer Don Munro said he would welcome the introduction of an eco-friendly anti-shark system that does not kill sea life.
Munro is president of the local boardriders club for Lennox Head and Ballina, two prominent surf towns on the NSW far north coast hit, which have been hit by a recent spate of shark attacks.
Since 2014, there have been at least 11 shark attacks, two of them fatal, between Evans Head and Byron Bay, a 70km stretch of NSW coastline that includes Lennox Head and Ballina.
In December last year, the NSW government began a controversial six-month trial of shark nets at five beaches between Lennox Head and Evans Head. Drum lines and shark nets.
Munro said the nets had worked and there was a “positive vibe” returning to the area, after it had been cast by some media as a kind of shark capital of the world.
“But the drums line and shark nets do kill sea life,” Munro said.
“The ultimate alternative is a system that would see humans and sharks co-exist.”
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