A “virtual shark net” that detects potential predators by recognising the way they swim is being tested at Sydney’s aquarium, following trials at sea.

The system, called Clever Buoy, uses a multi-beam sonar technology to produce an image of a marine animal, which is then matched against the known swimming patterns of sharks.

Richard Talmage, general manager of Clever Buoy, said the head and tail movements of different animals were distinct.

“Each species will swim slightly differently and we can distinguish between sting ray, a dolphin, a seal and a shark based on their size, shape and swim pattern,” he said.

If a shark is detected, the system can warn swimmers and surfers of the danger using a mobile or satellite network.

“When we detect an object, an alert can go out to beach authorities be that a ranger or surf lifesaver,” Mr Talmage said.

Ocean trials detect great whites

During an earlier trial, a Clever Buoy system was deployed to Bondi Beach. Photo: Clever Buoy

A four-week trial ocean trial at Hawks Nest, near Port Stephens has just been completed, involving the Department of Primary Industries (DPI) and the University of Technology Sydney (UTS).

Head of fisheries research at DPI, Natalie Moltschaniwskyj said she was very happy with the results in the field.

“We’ve had very clear water and we’ve certainly captured [white] sharks on the Clever Buoy and on our cameras,” she said

However, she said further analysis of the data was needed to see whether system was effective enough to warrant widespread use in NSW, alongside other systems like “smart” drumlines, GPS tagging and drones.

“We need to support that with research to make certain we make the best decisions about the technology we’re putting on our beaches,” she said.

During an earlier trial, a Clever Buoy system was deployed to Sydney’s Bondi beach.

Sea Life Aquarium to host trial

Clever Buoy uses a multi-beam sonar system to produce an image of a marine animal. Photo: ABC

The trials have moved to the controlled environment of Sydney’s Sea Life Aquarium, to assess the system’s ability to detect different types of sharks, including the grey nurse.

UTS Professor Bill Gladstone said he hoped the technology could be refined, so that swimmers are warned only about threatening species, not harmless sharks.

“Rather than say it’s a shark or not a shark, a potential advancement is to identify individual shark species,” he said.

The NSW government already uses shark nets on 51 beaches between the Illawarra and Hunter and recently announced a new netting program on the far north coast, following a series of attacks.

Professor Gladstone said he hoped technology like that used by Clever Buoy would reduce the need for nets in the future.

“The shark nets do catch other species, which does have an impact on the marine ecosystem, so we’re hoping advances in technology will lead to ways that we can mitigate that risk,” he said.

-ABC