Surfers at a high-profile surf competition in WA's South West are on high alert after a shark warning has been issued, triggered by schools of salmon beginning their migration along the coast.
The warning comes after WA's most prestigious surf event - the Margaret River Pro - kicked off on Wednesday, moving the first heat of the competition to North Point near Gracetown.
Surf breaks in the area off Gracetown have become notorious after three surfers lost their lives in fatal shark attacks along the stretch of coastline.
Surfer Chris Boyd, 35, was killed by a shark at Lefthanders Beach in 2013, the same break where Bradley Smith, 29, lost his life being mauled by a four-metre shark in 2014.
There were three fatal shark attacks in surf breaks off Gracetown. Photo: wannasurf.com
World-class surfers, spearheaded by legendary 11-times World Surf League Champion Kelly Slater, have travelled to the region to take part in the competition.
Fisheries WA released drone footage of salmon schools along the South West Coast, which also shows a number of large sharks hunting them.
"Reported shark sightings are already on the rise around schooling fish. If you're swimming or surfing, recognise the danger signs and keep away from large schools of fish," the video warns.
"The Westpac Lifesaver Rescue Helicopter patrols the South West on weekends and holidays. If the helicopter hovers and sounds the siren, stay out of the water for at least an hour and check your mobile for updates on shark activity before returning to the water."
A shark spotted by the Westpac Helicopter. Photo: Fisheries WA
Last weekend, the SharkSmart website recorded six individual shark sightings down south between Bunker Bay and Wilyabrup.
And over the last month, there have been 33 reported sightings by the helicopter between Hamelin Bay and Peppermint Grove Beach.
The Salmon bleeding at Smiths Beach captured by drone. Photo: Ian Wiese
The warning follows an incident at Smiths Beach last Wednesday, when Yallingup locals criticised fishermen for putting swimmers at risk of a shark attack after catching and gutting a salmon catch without warning at the popular swimmers beach.
Electronic shark deterrent devices have been set up around the Drug Aware Margaret River Pro in order to repel sharks.
