Using detection and deterrence technologies to help humans coexist with sharks
As temperatures soar, people swim a lot more than usual, especially in the ocean to beat the heat. Our Senior Environmental Scientist and Asia Pacific Senior Principal in Aquatic Ecology, Dr Craig Blount embraces this Australian way of life. He spends his weekends surfing Australia’s beautiful coastline and his weekdays managing coral and seagrass projects, fishery programs and researching shark and prawn behaviour.
Even though Craig is globally recognised as a shark expert, he admits that he used to be scared of them, but the more he learns about sharks, the more he loves them.
“Sharks are not as scary as you may think. The fact is that humans are not a normal food choice for sharks, and they are so misunderstood and falsely represented,” said Craig.
Contrary to popular belief, not all sharks are meat eaters. Filter feeders such as whale sharks are the world’s largest living fish that only feed on plankton. Unfortunately, they are also one of the many shark species that are endangered, mostly due to our activities – particularly commercial shark fishing. While sharking finning at-sea is illegal in Commonwealth fisheries, the sought-after flesh of sharks is widely sold for fish and chips in Australia.
“Sharks are inquisitive and they bite to investigate what is floating in the water. It is true that these apex predators are smart, but sometimes, cases of mistaken identity still happen,” he said.
Existing approaches to protect humans from potential shark bites can be broadly divided into two main categories: detection and deterrence. Shark detection approaches may include aerial surveys, land-based spotters, in-water observers and tagging. In terms of shark deterrence, physical barriers or mesh nets are commonly used – they may seem effective but other protected and endangered marine life are caught by the nets unintentionally.
Out of all water users, surfers have a higher risk of sustaining a shark bite given they tend to surf away from patrolled beaches, often in more remote places and in deeper water than swimmers.
Surfers could reduce the risk, by taking safety into their own hands and attaching a personal shark deterrent to their body. Sharks are known to have highly sensitive electroreceptors. These battery-powered, water-activated shark deterrents produce an electric field that disrupts sharks’ electroreceptors around the surfers. These devices are currently commercially available and some can be fitted to a surfboard,” he said.
Craig has reported on recent tests of a shark deterrent product which showed that, when active, it significantly reduced the risk of a shark bite and also provided more time for surfers to leave the water if a potentially dangerous shark were present.
Based on current knowledge, none of the technologies will achieve 100 per cent detection and deterrence. The best option for beach authorities is to choose a system that best matches the situation and local environmental conditions. For swimmers and surfers who don’t own a personal shark deterrent, Craig has one piece of advice.
“Sharks get excited about splashing activities and lots of movement. If a shark encounter does occur, stay calm and don’t move.
“Without sharks, the marine ecosystem may collapse. They play a crucial role in keeping the marine ecosystem healthy, for instance, by cleaning up weak and sick fish in the ocean. As technology advances, I believe we will find ways to co-exist with them peacefully and sustainably,” he said.
Craig is presenting his strategic ideas for living with sharks at the 2019 Australian Coastal Councils Conference in Kiama, NSW, Australia on 6-8 March. For more information, please see Craig’s contact details below.
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For more information contact:
Senior Environmental Scientist
+61 2 9024 7035