Le "SharkSafe Barrier™", un nouveau dispositif anti-requin testé à Saint-Paul et l’Étang-Salé
Le Centre de Ressources et d’appui de réduction du risque requin présente ce vendredi le "SharkSafe Barrier™", un nouveau dispositif pour lutter contre les squales à La Réunion. Testée en Afrique du Sud, cette barrière émet des ondes magnétiques qui repoussent les requins. Explications.
Les ondes électromagnétiques arriveront-elles à repousser les requins de nos côtes ? Le CRA, Centre de Ressources et d’appui (CRA) de réduction du risque requin présente ce vendredi 8 février un nouveau dispositif pour lutter contre les squales, le "SharkSafe Barrier™".
Une barrière visuelle et magnétique
Il s’agit d'une sorte de barrière qui émet des ondes électromagnétiques censées repousser les requins qui s’en approcheraient. Cette barrière est composée de matériaux et d'aimants qui ressemblent à une immense forêt d'algues dans laquelle les requins évitent souvent d'entrer. "Il y a une double barrière visuelle et magnétique qui repousse les requins", explique Olivier Bielin, directeur du CRA.
Ce dispositif va désormais être installé au large de la plage de l’Étang-Salé ainsi qu’en baie de Saint-Paul. Les tests vont durer environ deux ans. S'ils sont concluants, cette barrière sera étendue aux plages de l'Ouest comme Boucan et les Roches Noires.
Un succès en Afrique du Sud
Conçus en Afrique du Sud, ces appareils ont déjà été testés durant cinq ans dans le pays. Selon le CRA, ils se sont révélés efficaces car ils ont permis de repousser des squales. Il s’agissait toutefois de grands requins blancs, alors qu’à La Réunion ils devront repousser des requins bouledogue et tigre, souligne le CRA. Le Centre précise aussi que ces appareils sont sans conséquence sur la faune locale et qu'ils résistent aux fortes houles en Afrique du Sud.
Ce dispositif sera-t-il efficace à La Réunion ? La réponse dans les jours qui viennent selon le CRA.
'100 percent safe' shark barrier could be deployed on NSW beaches
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).
A NSW DPI spokesperson told Nine.com.au that the potential of the SharkSafe barrier was discussed by international shark experts at the 2015 Shark Summit, hosted at Sydney's Taronga Zoo.
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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This farmer's prize-winning feed is not for the birds
09 November 2017 - 12:15 by Kgaugelo Masweneng
An Eastern Cape-born businessman will be representing South Africa at the Cleantech Open Global Forum competition next February in Silicon Valley in America for his innovative use of dehydrated worms to make animal feed.
Bandile Dlabantu‚ who won R120‚000 after winning first place in the local competition‚ said his dream was to expand his brand to other African countries.
“I’m excited. This has opened a lot of opportunities. There is traction on partnership and investments too. I would like to see the product expanding throughout South Africa and East African countries. The project started three years ago and a lot of sacrifices went into it. At times we had to go without salaries. Things were not always great‚ things take time‚” Dlabantu said.
Given his entomology background‚ being inventive with worms has become an almost natural progression for Dlabantu.
The product can be fed to a number of insect-eating reptiles and birds‚ and can also be used as a protein and energy source in formulated diets for mono-gastric animals like chickens‚ pigs and fish.
The feed by Dlabantu’s company‚ Khepri Meal™‚ is said to be cheaper than conventional feed‚ reducing the cost of animal farming.
Dlabantu said his company grows and harvests the worms.
On November 3 Minister of Science and Technology Naledi Pandor presented the grand prize to Dlabantu at a gala event in Pretoria.
The runners-up were Sara Andreotti‚ whose SharkSafe Barrier™ is an eco-friendly alternative to the shark nets and baited drumlines that prove lethal to a wide array of marine life‚ and Euodia Naanyane-Bouwer's Gracious Nubian washable and reusable sanitary pads.
They received R60‚000 each and will both be joining Dlabantu at the Cleantech Open Global Forum next year.
SharkSafe Barrier™ could protect local swimmers
Magnetic, kelp-mimicking screen from South Africa has UMass Dartmouth connection.
By Rich Saltzberg October 12, 2018
The increasing presence of great white sharks in Massachusetts waters had many people thinking twice before taking a dip this past season, especially after the tragic death of 26-year-old Arthur Medici in Wellfleet. The gray seals that white sharks prey on are not only multiplying, but expanding their territories, with colonies now reported on Nomans Land off Aquinnah, and Gull Island amid the Elizabeth Islands. Between the Cape, which teams with thousands of seals, Nomans Land, and Gull Island, the Vineyard finds itself within a triangle of shark food. How Vineyarders can keep these enormous fish at bay — keep them from straying close to beaches and potentially mistaking the outline of a swimmer for that of a seal — is a question gaining increasing currency. A South African startup may have the answer with an screen system called SharkSafe Barrier™.
The barrier is a submarine wall of tubes meant to look like a kelp forest. The researchers who developed the barrier calculate sharks are loath to enter kelp forests.
“Sharks need to constantly swim to oxygenate their gills,” marine biologist Sara Andreotti, SharkSafe Barrier™ general manager, said, “so they are likely to avoid an environment that can trap them, obstruct their gills, or simply constrain their movements, such as a thick kelp forest.”
The strands of artificial kelp are also laced with barium ferrite magnets. The magnets irritate electroreceptive pores in shark’s snouts. Sharks use the pores to sense electricity and magnetism. The magnets don’t hurt the sharks, Andreotti said, but they overwhelm the electroreceptive pores, acting as a further deterrent. The magnets do not require shore power, and are encased in a ceramic shell and don’t therefore corrode, she said.
“Michael Rutzen [South African cage diver] had the idea of building an artificial kelp forest as a shark deterrent, to substitute for shark nets, for several years, following his firsthand experiences in diving with the white sharks in open waters,” Andreotti said. Rutzen’s goal was to stop shark deaths from traditional net barriers and drum lines.
Rutzen and Andreotti later met Craig O’Connell, a former Ph.D. candidate at the University of Massachusetts, Dartmouth, who was developing barium ferrite magnets for use in trawler nets to help avoid shark bycatches. The three then translated the magnet idea to the faux-kelp barrier. Andreotti personally tested the barrier by free-diving into chummed waters.
“After the sharks arrived, I had to jump inside the barrier,” she said. “I would say I have a lot of faith in this system.” The white sharks did not attempt to breach the barrier, she said.
Andreotti said she did not believe a white shark chasing a seal would enter the faux-kelp barrier. “If a shark is chasing a seal, it is unlikely that the shark can still swim through four rows of SharkSafe Barrier™,” she said. Four rows is the recommended beach design for human safety, she said. Seals pass through it harmlessly, she added. “We are at the stage where we can install the barrier in areas with rocks or less than one meter of sand.”
The kelp barrier “must be about one meter above the water at high tide,” she said. The plastic composing the barrier can be made from 100 percent recycled material.
The barrier runs about $35 per square meter, “calculated on 20 hectares of surfable water,” she said.
The strands of faux-kelp are manufactured in South Africa, while the concrete anchors are molded onsite by a local subcontractor.
Shark attack capital of world trials new eco-friendly shield to halt deaths
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 "sharkman", for feats such as hitching rides on the dorsal fins of 4-metre great whites.
"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 large number of sharks and other animals that perish.
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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