5:24pm Aug 6, 2019
Scuba diving at a beach where water sports are banned because of so many fatal shark attacks is not for the faint-hearted.
But when you’re in the business of testing ways to stop great white sharks and other great ocean predators, then these are the kind of perilous locations you’ll inevitably find yourself in.
In May last year marine biologist Dr Sara Andreotti suited up and slipped into the dicey waters of Reunion Island, a small island in the Indian Ocean which has been hit by a spate of deadly sharks over the past decade.
The University of Stellenbosch researcher was partnered up with dive buddy and fellow South African Mike Rutzen, a man with an international reputation for free diving with great white sharks.
The pair were there to scope out the sea bed of a dangerous beach in Saint-Paul, where local government, eager to solve Reunion’s shark attack dilemma, had invited them to install a prototype of their sharksafe barrier shield.
Since 2011, there have been 30 shark attacks in Reunion, killing 11 people. The tiny French island, 175km to the east of Madagascar, was quickly anointed the shark attack capital of world.
Despite the ominous statistics, Andreotti says she wasn’t nervous to be in the water.
“You are busy working and not thinking about being in shark infested waters,” Andreotti says.
It helped that water visibility in the Bay of Saint-Paul that particular day stretched to as much as 50 metres. It also helped that she was with Rutzen, known globally as “
“Mike’s expertise diving with sharks outside the cage is huge,” Andreotti says. “That’s why we do this together.”
Andreotti and Rutzen measured, prodded and scanned the sea floor as methodically as possible, all the while vigilantly scanning for looming dark shadows.
The sharksafe barrier is made up of a series of dark coloured floating pipes anchored vertically to the ocean floor. The dark pipes, lined with magnets, sway and drift in the ocean, very deliberately mimicking the appearance of a kelp forest.
Rutzen had concepted the design after observing seals in Cape Town’s notorious shark alley racing into forests of kelp to escape being killed by great white sharks. Time and again, on approaching the kelp, the sharks would turn away and refuse to enter these areas.
Not a single great white or other shark had breached their barrier in six years of testing in Gansbaai, a coastal settlement in South Africa’s Western Cape, Andreotti says.
After that initial scoping dive in Reunion, a sharksafe barrier test grid was installed at the Bay of Saint-Paul. Twice a week a diver would go down and chum the waters with blood and rotten fish guts inside the 10m x 10m walls, made up of 200 floating pipes.
After six months of testing in Reunion, no sharks had entered the barrier, Andreotti says.
“It is actually a square that is now full of fish. No sharks have penetrated or even come near the barrier.
An artificial reef has started to grow on the concrete blocks. Seaweed and organic matter is attracting small fish, which in turn brings in bigger fish.
Andreotti points out that sharks, dolphins, turtles and other sea creatures cannot get caught up and die in the barrier. One of the biggest criticisms levelled at shark nets by conservation groups is
The latest data from NSW’s shark netting program, covering the period between September 1 2018 and April 30 2019, has revealed nets at some of the state’s most popular beaches has killed hundreds of animals, including endangered species.
A total of 395 animals were trapped in nets protecting 51 beaches from Newcastle to Wollongong – but only 23 were targetted species: white, bull or tiger sharks.
Since the nets were introduced across NSW in 1937 there has been one fatal shark attack and 33 unprovoked interactions, according to NSW Department of Primary Industries data.
Andreotti wants to bring the sharksafe barrier to Australia.
She claims her system deters sharks much more effectively than nets or drum lines, and that crucially there is no deadly impact on marine life.
“We are as ready as we’ve ever been,” she says.
“Here is a solution to take nets and drum lines out of the water. Animals are dying.”
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