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Killer whale sounds to scare away sharks

Killer whale sounds to scare away sharks

WA scientists will broadcast killer whale "screams" through underwater speakers this summer to see if they scare away great white, tiger and hammerhead sharks from Perth beaches.

The University of WA research is the latest bid by scientists to better understand the sharks and safeguard swimmers after a horror spate of attacks in the past two years.

It also comes after an ABC program last night suggested killer whales, or orcas, were the great white shark's only natural predator - a theory long held but, until now, little tested.

UWA Associate Professor Nathan Hart, a sensory neurologist, said mimicking killer whale calls through soundwaves had been shown to deter sharks.

But Professor Hart said the idea was last tested in the 1970s and did not involve big predatory sharks, meaning little was known about how effective it would be with white pointers.

Under the new trial to begin in January, researchers will try to lure tiger and great white sharks before broadcasting the replicated sound of a killer whale to determine whether the predators react.

Depending on its success, the trial could pave the way for the technology to be used as a shark deterrent off Perth beaches including Scarborough and Cottesloe, where conditions make shark barriers unsuitable.

"With a little bit of anecdotal evidence and possibly the odd YouTube video I think it's accepted that killer whales are natural predators of most sharks," Professor Hart said. "They (researchers in the 1970s) basically analysed the call of the orca and tried to pull out the essence of it and this was shown to make sharks go away from the test area.

"Given we have access to white sharks and tiger sharks and hammerheads . . . up and down the WA coast, it's a really good idea to visit this in case it's got legs.

"But it's very early days."

Despite the optimism, Professor Hart said mimicking killer whale sounds would not be a panacea for the safety of swimmers because sharks could become "habituated" to it if overexposed.

"We're testing lots of repellents at the moment and sometimes they work and sometimes they don't work," Professor Hart said.

Premier Colin Barnett has lauded the research, which is being carried out as part of multimillion-dollar efforts to test the effectiveness of existing deterrents and investigate new ones.