‘Friendlier’ shark barrier designed by SA boffinsComment on this story
Cape Town - Stellenbosch University scientists have developed an eco-friendly shark barrier which can be used as an alternative to a shark net.
The barrier is called “Sharksafe”.
Shark nets were introduced to reduce the number of shark attacks on swimmers but they have resulted in the death of other sea animals including dolphins andturtles.
Countries including Australia, Japan and the US are looking at alternatives to shark nets while in Cape Town new shark exclusion nets which can be removed daily have also been developed.
Professor Conrad Matthee, head of the Department of Botany and Zoology, said shark numbers had decreased by up to 90 percent over the past 20 years, “particularly the number of great white sharks”.
“Sharks are top predators and if they were to be taken out of the ecosystem, the latter will be disrupted. ”
The barrier is made of rigid upright pipes which resemble kelp when it floats in the water.
“The structure also contains magnets to make it effective for various shark species. The pipes are anchored to the seabed and stand upright up to the height of the water level during high tide.”
Matthee said a magnetic barrier that resembled kelp had been chosen because certain shark species, such as the Zambezi shark found in KwaZulu-Natal, were sensitive to strong permanent magnetic fields, while others, like the great white shark in the Cape waters, did not like kelp at all.
“We, for instance, saw how seals chased by sharks swam into kelp and how the sharks time and time again turned away, not entering the kelp areas” Matthee said.
During research, the team put bait behind the barrier to attract sharks but no sharks swam through the barrier.
The sharks were also deterred by the magnetic fields, he said. - Cape Argus