WATCH: Panic as man is bitten in second shark attack in hours

Horrifying footage has shown the panic and thrashing in the water as a second Perth surfer was attacked by a shark within seven hours.

Alejandro Travaglini, 37, needed surgery to both legs after he was mauled at Cobblestones beach in Gracetown on Monday, while Jason Longgrass, 41, walked to an ambulance after he was bitten on the leg at the nearby Lefthanders break.

A few hours after the first attack, surfers ignored the beach closures and got back in the water.

Shocking footage shows thrashing in the water as a person on shore screams to the surfers to come in.

"Shark!" he can be heard yelling repeatedly as he films the movement in the ocean.

Shocking footage shows thrashing in the water as someone yells for the surfers to come in. Photo: 7 News

Mr Longgrass said he went to slap the water, but the shark accelerated toward the board.

He made a dash for the beach and with the adrenaline kick didn’t realise he had been bitten on the leg until he was on dry land.

The first attack victim, Mr Travaglini, is now stable in hospital after having surgery.

A whale carcass believed to be attracting sharks to the area was removed on Tuesday.

The Margaret River Pro surfing competition is being held about 15km away from where the attacks took place, but Brazilian surfer Italo Ferreira has expressed concern on social media about sharks.

"Two shark attacks in less than 24 hours here in Australia, just a few kilometres from where the event is being held," he said on Instagram.

A few hours after the first attack, surfers ignored the beach closures and got back in the water. Photo: 7 News

"Don't you think that's dangerous? Is the safety of athletes not a priority?

"I don't feel comfortable training and competing in places like this."

Fellow Brazilian surfer Gabriel Medina also said he did not feel safe training and competing in areas where "any time, something can happen to one of us".

The Margaret River Pro was suspended for one hour on Monday, before resuming with enhanced safety measures, including skis and drones.

Jason Longrass was bitten by a shark near Cobblestones Beach, southwest of Perth on Monday. Source: 7 News

The international event was called off on Tuesday due to poor conditions, but organisers also warned competitors not to surf in the area.

"We have actioned our well-established safety protocols and are gathering all the latest information to determine the next steps," the World Surf League said.

"We will continue to liaise with all involved, most importantly the surfers. Their safety remains paramount."

Mr Travaglini worked as a crew member at the surfing competition.

Mr Travaglini was transported to hospital after being bitten by a shark. Source: 7 News