A West Australian man who lost his leg when he was attacked by a shark south of Perth on Tuesday has died in hospital.

Ben Gerring, 29, was critically injured when he was mauled by a suspected great white shark while surfing off Falcon in Mandurah.

The fly-in, fly-out worker was pulled from the water by fellow surfers and received CPR on the beach before being taken to hospital.

He died in Royal Perth Hospital Friday night from his injuries.

Witnesses at the scene on Tuesday said Mr Gerring's leg was severed above the knee.

The WA Department of Fisheries (DoF) has said the damage to his surfboard indicated he was attacked by a great white shark.

Mr Gerring is the 13th person to die from a shark attack in WA since 2000.

Fatal shark attacks in WA since 2000 Spearfisher Jay Muscat: Cheynes Beach December 29, 2014

Spearfisher Jay Muscat: Cheynes Beach December 29, 2014 Surfer Chris Boyd: Gracetown November 23, 2013

Surfer Chris Boyd: Gracetown November 23, 2013 Surfer Ben Linden: Wedge Island, July 14, 2012

Surfer Ben Linden: Wedge Island, July 14, 2012 Diver Peter Kurmann: Geographe Bay, March 31, 2012

Diver Peter Kurmann: Geographe Bay, March 31, 2012 Diver George Wainwright: Rottnest Island, Oct 22, 2011

Diver George Wainwright: Rottnest Island, Oct 22, 2011 Swimmer Bryn Martin: Cottesloe Beach, Oct 10, 2011

Swimmer Bryn Martin: Cottesloe Beach, Oct 10, 2011 Surfer Kyle Burden: Bunker Bay, Sept 4, 2011

Surfer Kyle Burden: Bunker Bay, Sept 4, 2011 Surfer Nick Edwards: Gracetown, Aug 17, 2010

Surfer Nick Edwards: Gracetown, Aug 17, 2010 Snorkeller Brian Guest: Port Kennedy, Dec 27, 2008

Snorkeller Brian Guest: Port Kennedy, Dec 27, 2008 Snorkeller Geoffrey Brazier: Abrolhos Islands, Mar 19, 2005

Snorkeller Geoffrey Brazier: Abrolhos Islands, Mar 19, 2005 Surfer Brad Smith: Gracetown, July 10, 2004

Surfer Brad Smith: Gracetown, July 10, 2004 Swimmer Ken Crew: North Cottesloe, Nov 6, 2000

Mr Gerring's brother Rick thanked the "heroes" that brought his injured brother back to shore and the medical staff who cared for him throughout the "traumatic ordeal".

"The hospital staff gave us those [three] days [with Ben]. Obviously we were always hoping for the best outcome, it was always at the back of our minds that this could happen, but they gave us that time to say our goodbyes," he told ABC News.

Rick Gerring said his brother was a naturally gifted sportsman, whether it was track and field, skateboarding, snowboarding or surfing.

"Ben loved the ocean, crabbing and surfing but his greatest love is and always will be Jasmine; he was so proud to become a father and a husband," he said.

Mr Gerring's fiancee Jasmine Boyer is pregnant with their first child.

"That is the hardest part and I can't even imagine what Jasmine is feeling right now, but … we will always support Jasmine and my nephew or niece. We will do everything to be there," Rick Gerring said.

A 4.2-metre shark was caught on Wednesday afternoon on a baited drum line set up near where Mr Gerring was attacked.

However the Department of Fisheries (DoF) said it was not possible to tell if that shark — which was not tagged — was responsible for the attack.

The shark died on the line and was disposed of at sea, and beaches in the area were reopened to the public on Friday.

A crowdfunding campaign which was set up to help Mr Gerring and his fiancée has raised more than $34,000 in three days.

'Rest in surfing paradise Benny'

Tributes to Ben Gerring have been placed at Falcon beach. ( ABC News: Armin Azad )

Mr Gerring grew up in the Mandurah area and was well known among local surfers.

Flowers and surfboards have been left by friends and locals at the surf spot known as Gearies where he was attacked, while tributes have also been paid on social media.

Local surfer Pete Beardmore visited the beach and told reporters Mr Gerring's death had "hit the community pretty hard".

"To wake up this morning to see that news ... I was shattered," he said.

"I'd say what we thought was a safe environment no longer feels safe ... the sightings of sharks we've seen have increased but they were never felt as an imminent threat, but now it's very real.

"Everyone knows the risks and it's a fear that sits in the back of your mind every time you go out there."

Surfing WA events manager Justin Majeks told 720 ABC Perth Mr Gerring's death was a tragedy.

"I think a few people who were in the water on Tuesday are going to certainly take some time to get over the things they saw and witnessed," he said.

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Attack sparks fresh shark debate

The DoF has defended shark warnings issued on the day of the attack.

The sighting of a 3.5-metre shark off Pyramids Beach, about five kilometres south of the attack, had been reported earlier in the day, but the DoF said no action was required as it was 1.8 kilometres off the coast.

Sorry, this video has expired Shark caught on drum line after surfer attacked ( ABC News )

Alerts were instead posted on the DoF's Shark Smart website and the Surf Life Saving Twitter account.

Meanwhile the WA Government has ruled out a return to permanent drum lines off Perth beaches.

The Government was heavily criticised when it placed drum lines off beaches in 2013 in response to seven shark deaths.

"The policy did not prove effective in catching great whites and the great white shark was principally the problem," Premier Colin Barnett said on Thursday.

However Mr Barnett defended the Government's efforts to keep beaches safe, and said it would continue to hunt and trap sharks it believed were a threat to swimmers.

The Opposition said it was opposed to catching and killing sharks, describing it as silly.