A shark-sensing "buoy" and a fake kelp forest that is actually a high tech shark barrier could soon be deployed at beaches to help prevent shark attacks, which led to 10 deaths last year and dozens of serious injuries.
The new inventions could be a win for sharks as well as humans, since both systems do not harm sharks. Shark culling as well as drum lines, which brutally capture large sharks using baited hooks, are still common at beaches around the world, so it’s hoped that more high tech methods will soon replace the very eco-unfriendly practices.
Craig O'Connell, founder of the marine conservation non-profit O’Seas Conservation Foundation, helped to develop the Sharksafe Barrier, which is designed to resemble a kelp forest and includes magnets that deter great white, bull, hammerhead, tiger and other shark species. Its success is documented in a paper that will be published in the November issue of the Journal of Experimental Marine Biology and Ecology.
"The current Western Australian shark cull is a short-term solution that may have long-term negative consequences on the marine ecosystem," O'Connell, lead author of the paper, told Discovery News. "Our barrier does not use netting or hooks, but rather stimuli that non-invasively deter sharks away from a region, whereas other marine life can simply swim through the barrier."
Testing has determined that marine mammals, such as Cape fur seals, pass through the barrier unimpeded. Abalone, a sea snail whose population has been in global decline, seem to love the Sharksafe Barrier, attaching themselves to it as they would to a rocky substrate.
As for its shark-repelling properties, O’Connell explained that sharks, skates and rays have a unique electro-sensory system known as the ampullae of Lorenzini, whereas most animals do not. The researchers therefore believe that the magnets within the Sharksafe Barrier specifically target sharks and their relatives.
"As a shark approaches the magnet," O'Connell said, "we hypothesize that an electric field is induced that may overwhelm the electro-sensory system of these sharks," causing them to avoid the area and swim in the opposite direction.
Additionally, sharks tend not to enter high-density natural kelp forests, which is why prey of these toothy hunters so often seek refuge in kelp. Just the look of the Sharksafe Barrier, made up of three to five rows of large vertical pipes, can put a shark off.