Shark policy expert skeptical about deterrent cable for Perth beaches

The South African board at the leading edge of shark deterrence technology says it can bring an electrical "shark cable" to Perth within a few years.  Photo: Morne Hardenberg/Atlantic Edge
The South African board at the leading edge of shark deterrence technology says it can bring an electrical "shark cable" to Perth within a few years. Photo: Morne Hardenberg/Atlantic Edge
WA's shark cull policy was a controversial one and it's a good sign the conversation is moving to deterrence, experts say.  Photo: 4BC Afternoons

WA's shark cull policy was a controversial one and it's a good sign the conversation is moving to deterrence, experts say. Photo: 4BC Afternoons

A shark policy expert has tempered excitement with 'healthy skepticism' about new cable technology promising to head off great white sharks from Perth beaches.

The South African government's Sharks Board has declared its trial of a 100-metre electronic 'pulsing' cable running offshore, parallel to a Cape Town beach, a success.

Project manager Paul von Blerk told The West Australian the government would produce a commercial version of the $1 million cable, harmless to sharks and humans, for use by governments including Perth for about $200,000.

Christopher Neff, who has studied West Australian policy for years and did the world's first doctorate on global government policies reacting to shark bites, said the board had led electrical shark deterrent technology for 20 years but the technology had been 'hit and miss' because of geographical variations in salinity and water density and movement.

Dr Neff said WA beaches were different from others in terms of how quickly they became deep and while effective non-lethal deterrence was a "huge step in the right direction", the total ecological impact was still uknown.

"I would be very interested in to know how it affects ocean swimmers with pacemakers, whether its efficiency changes depending on the swell or salinity or weather. Usually you need a stable ocean environment and a low-energy beach for something like this. And would it go out to the surf line? Is there a study of the long-term environmental impact?" he said.

"Whenever we introduce anything alien into the water we need to be acutely aware of the long-term effects. If it deters sharks it's great, but the odds are if it affects an apex predator like a shark that's at the top of the food chain, it will affect little things as well.

He believed funds to be spent on shark policy should go on public education.

"The number one thing that will help people is a better understanding of their role in the water, the risks they are taking," he said.

"Having said that, I am in favour of non-lethal deterrence technology."

He assumed an Australian trial would probably be funded by the state, but all three tiers of government in Australia were involved in some way with shark research and policy and so it could be a question of "who jumped first".

Curtin University Centre for Marine Science and Technology director Christine Erbe said long term issues that could affect the electric field could include corrosion or substances growing on the cable underwater.

Environmental issues would also require study.

While peer-reviewed scientific publications on the new technology had yet to emerge, the South African Shark Board had decades of experience.

"It sounds very positive and exciting. Let us wait and see," Dr Erbe said.

Lindsay Lyon is managing director of Shark Shield, the market's only proven personal electrical repellent device, developed by West Australian entrepreneurs from the South African technology released in the 1990s.

He said it could only ever be a small part of an integrated system.

"It is great technology, no doubt, and provides the general public with a level of confidence," he said.

"Paul [von Blerk] ... has been involved with this technology right from scratch so if he says he's getting 100 per cent success, he's getting 100 per cent success.

"But when you look at the people at risk, those who represent 80 per cent of the unfortunate interactions with sharks, they are surfers or divers and none of them will be protected by a beach barrier.

He said education for people to remove or mitigate the personal risks they ran were essential, but he was glad the conversation was moving away from culling.

"You can't call on the government to kill all the sharks for you," he said. 

This story Shark policy expert skeptical about deterrent cable for Perth beaches first appeared on WA Today.