Mullaloo shark protection goes hi-tech

Whitfords Volunteer Sea Rescue helps Mullaloo Surf Life Saving Club to deploy a shark detection buoy.
Whitfords Volunteer Sea Rescue helps Mullaloo Surf Life Saving Club to deploy a shark detection buoy.

A SHARK attack in June 2012 left a lasting impression on members of Mullaloo Surf Life Saving Club.

Martin Kane was paddling with four fellow club members about 1km south of Mullaloo beach when a shark hit the back of his surf ski and knocked him into the water about 150m from shore.

Mr Kane was unharmed but club president Carlo Tenaglia said the fear, worry and reality of the incident hit the club.

“We had always known sharks were out there but we were never too concerned,” he said.

“We’d had a few sightings but this was out of the blue.”

The incident prompted the club to form BeachLAB – a group to research where and how technology could help prevent a similar situation.

Through a partnership with Curtin University’s Centre for Marine Science and Technology, the club has developed a world first shark monitoring system for the detection and warning of tagged sharks at Mullaloo.

Mr Tenaglia said the club’s system complemented the Department of Fisheries’ project that has two receivers about 600m from shore at Mullaloo beach to detect tagged sharks within 250m to 400m of the buoy.

He said the Fisheries project had shown marginal success but if a tagged shark was detected, there was a delay of up to two minutes before it was reported via text message or posted on Twitter and most people would not have access to a phone when on the beach.

He said the club wanted to develop a system similar to Fisheries’ but not have it connected by satellite because it was too slow.

Placed about 200m offshore and 500m apart, the club’s two buoys are directly connected to its Beach Safety Command and Control radio system that receives the tagged shark detection and immediately activates a warning siren and flashing light to alert beach users.

The system was developed and buoys deployed using donations, funding from the club and volunteers’ time including Whitfords Volunteer Sea Rescue.

The buoys are constantly “self-checking” by sending a message every 10 minutes to show they are still working and a message every 30 minutes to notify they are still detecting tags placed in the water for testing.

“It isn’t fool-proof and neither is people watching from the beach but it’s a better level of detection,” Mr Tenaglia said.

“It’s about raising the effectiveness of patrols on the beach.”

The system can also be used on unpatrolled beaches and has been designed to be used in remote areas, such as surfing beaches in the South-West, powered with solar panels or batteries.

Mr Tenaglia said with the club’s and Fisheries’ buoys, there was about one square kilometre of coverage but the desire was to create a “virtual curtain of sonar detectors” along the beach, which could also detect untagged sharks.

Only about 200 to 300 sharks have been tagged.

He said the group had done some studies into the technology but funds to enable more trials were limited.

“There is still quite a bit of work and science to do,” he said.

“This is people’s lives so we want to be confident it works.”

He said it would cost about $600,000 to set up sonar receivers to cover the beach’s 4km coastline.

He said the club had also looked at using drones, which would be costly, and aerial surveillance but its success depended on many conditions including the sun, clouds, sea breeze and waves and the helicopter patrols were infrequent.

The BeachLAB group has also been researching underwater acoustics and how to create a negative sound to mask the noise of people in the water and create a silent environment to deter sharks from the area.

Mullaloo SLSC was a finalist in the community category of the WA Information Technology and Telecommunications Alliance’s 2015 Incite Awards for its shark detection radio system.