Skipper watches as sharks attack diver

File Photo / Supplied

A boat skipper watched helplessly as two sharks took an abalone diver off South Australia, leaving no trace of his body.

Skipper Howard Rodd told police he saw the sharks, believed to be white pointers, grab Peter Clarkson and pull him under as he surfaced from a dive on Thursday off Perforated Island near Coffin Bay on SA's west coast.

Mr Rodd radioed for help and searched the area for some time before making his way to shore where he was treated for shock.

A more extensive search for Mr Clarkson's body and his equipment proved fruitless on Friday.

Police said Mr Clarkson, 50, was not diving inside a shark cage and it was not known if he was using an electronic anti-shark device.

But he was wearing a shark deterrent when he encountered a four-metre great white in 2002 off Kalbarri in Western Australia.

"I was making a slow ascent when I realised that I was no longer alone," he said in a testimonial for the SharkShield device on the manufacturer's website.

"It was a scenario I had rehearsed in my mind a thousand times during the 27 years I have been diving, but this was the first shark of this species that I had encountered underwater.

"Head-on, the shark was a very intimidating sight and prior to this moment I never really felt threatened by its presence.

"To say that I felt safe would be an overstatement - one feels very vulnerable dangling solo off a line in 50m of water in the presence of a 4m great white shark - but the SharkShield gave me the confidence to complete my decompression and avoid a possible incidence of the bends.

"The last I saw of the shark was its tail disappearing."

Mr Rodd also had a close encounter at sea in November 2000 when his boat overturned in rough conditions while he and a colleague were diving for abalone.

Mr Rodd swam about 15 kilometres, spending an estimated 12 hours in the water before making it to shore.

His colleague, 48-year-old Danny Thorpe, stayed with the boat and either drowned or was taken by a shark. A coroner ruled his cause of death could not be determined.

Friends of Mr Clarkson said he was a popular and personable man. He divided his time between Port Lincoln, on Eyre Peninsula, and Esperance in WA.

According to his Facebook page, he was single and had studied zoology and economic geology at the University of South Australia.

He described himself as quite an independent person.

"I don't suffer fools easily but am a loyal friend, generous, open, honest and compassionate," he said.

Fellow diver Mark Payne said his mate would be missed but described him as a conservationist who would not want to see great whites hunted down.

"I don't think he would like to see us all going out there and killing all the great whites that we see," Mr Payne told ABC radio.

Those sentiments were echoed by the Abalone Industry Association of South Australia which does not support a cull, despite reports that great white numbers are increasing because of their protected status.

"There's always interactions each year with white sharks, and divers do as much as they can to reduce that interaction," executive officer Samara Miller told reporters.

"It's a calculated risk and the divers make the call on the day."

Darian Gale, who runs dolphin and eco tours at Coffin Bay, said sharks were a fact of life in the area.

"There has always been sharks down there. If you just look back through the history of it, every two to three years there seems to be an attack of some sort over this way," he said.

Before the latest incident, 19 people had been killed and 53 attacked by sharks in South Australian waters in the past 200 years.

- AAP