KILLING The shark that mauled Mandurah surfer Ben Gerring would be pointless, an expert says.

Ben Gerring, 29, is fighting for his life in hospital after being bitten while surfing at a spot known as Gearies at Falcon, south of Perth, on Tuesday afternoon.

The beach has been closed while Department of Fisheries officers try to catch the shark, believed to be a white pointer at least three metres in length.

The WA government dumped its controversial baited drum line trial in 2014 after the environmental watchdog recommended against extending it, but is allowed to implement its “imminent threat” policy for any shark larger than three metres that poses a risk to public safety.

University of Sydney lecturer Christopher Neff, who wrote the first doctoral thesis on the politics of shark attacks, said it was pointless to kill the shark suspected of the attack.

“The catch and kill policy is not a shark bite prevention policy — it is political theatre,” he told AAP.

“And it’s a shame because it basically takes a terrible situation that happened to people, like this gentleman, and makes it worse by suggesting the solution to the problem is to kill an individual shark.

“That’s not the solution to the problem.”

Dr Neff, who has tagged white sharks in South African waters, said baited drumlines made the beach more dangerous as they brought in more sharks.

After Texan man George Wainwright was killed by a shark while scuba diving at Rottnest Island in 2011, drumlines were set, but they had to be brought in within a few hours because they attracted large numbers of tuna, followed by white sharks that sought to prey on the fish.

Of all of the measures being tested or used to reduce the risk of shark attacks, Dr Neff singled out tagging programs as being most effective.

“It is actual risk reduction, actual public education that the public should use.

“That technology is a significant advancement that is being used in Cape Town and being picked up around the world.”

Ultimately, however, swimmers and surfers had to recognise the inherent risks of venturing into the ocean.

“We’re land animals — when we go in the water, everybody knows about it. The whole ecosystem responds,” Dr Neff said.

“We need to recognise the ocean is this wild, dynamic ecosystem and when we enter into it, we’ve got to have a healthy respect for that environment.”