Surfers and school children have been evacuated from a Secret Harbour beach twice in the past week after a Surf Life Saving WA drone spotted two sharks within 100 metres of swimmers.
SLSWA general manager Chris Peck said the drones were introduced at five popular Perth beaches two weeks ago as part of a new strategy to protect beach goers.
The two sharks were spotted at Secret Harbour by drone on Monday and December 4.
"Our drone patrol at Secret Harbour during a routine patrol has picked up a shark off the back of a break on Monday morning," Mr Peck said.
"It was about 300 metres south of the patrolled area, closer to the Rockingham side, but it was tracking down toward the flags about 100 metres off-shore, swimming in a zig-zag pattern.
"There were about 20 surfers in the water at the time and two school groups with about 30 kids in each so the drone is a great benefit from a localised surveillance perspective... we're able to take immediate action."
The shark was estimated to be around 2.5 metres long, but its species was unknown.
A week earlier, a three-metre shark had led to surfers and another school group being removed from the water.he drones are being used by SLSWA lifeguards at Secret Harbour, Cottesloe, City Beach, Mullaloo and Quinns-Mindarie beaches, with patrollers undertaking training to operate the devices.
Mr Peck said the drones also assisted lifeguards to know when it was safe for swimmers to return to the water.
"Instead of having to wait on a helicopter to come by, we've got the drone so we're able to use that to track the shark for longer to determine if it's still in the area.
"We tracked Monday's shark for about an hour, it kept heading south and eventually moved further out to sea."
The drones - which also help lifeguards to spot rips and bait balls which could attract larger marine life and swimmers in trouble - under Australian law must not be flown within 30 metres of a person and must always be within the pilot's line of sight, which is around 400 metres.
Mr Peck said SLSWA hoped to expand the drone patrol program next summer, and reminded ocean users that its lifesaving drones were clearly identifiable by their trademark red and yellow colour.
"The public can have confidence when they see the red and yellow drone from our people they know we're doing it in the right way," he said.
"When they see them they can have the trust it's Surf Life Saving doing it and not just a recreational user."
Since the beginning of summer to Monday afternoon, the Westpac SLSWA Helicopter has spotted more than 40 sharks along WA's coast, lifeguards have reported nearly 20 shark sightings - two by drone - and the public has reported around 20 shark sightings.
The majority of public shark sightings were off Rockingham near popular cray fishing areas.
Fisheries detected 11 tagged tiger sharks - mostly off Rottnest Island.
Eight beaches were temporarily closed due to shark sightings, with Bunker Bay closed on five occasions and Secret Harbour and Mindarie Beach closed on two occasions.
For real time Surf Life Saving WA beach and shark updates, please follow @SLSWA on Twitter.
