Hunt for killer shark continues, patrols stepped up

ADELAIDE - Fisheries officers today continued looking out for the 5m shark that killed a teenager at an Adelaide beach and patrols were stepped up as weekend crowds took to the water.

The South Australian government has authorised police and fisheries officers to destroy the shark that killed 18-year-old Nick Peterson at West Beach in Adelaide on Thursday.

A helicopter and a fixed wing aircraft today joined about 50 boats patrolling the beaches around Adelaide on the lookout for sharks.

Thursday's attack has rattled beachgoers and, as temperatures soared in Adelaide today, Surf Lifesaving South Australia chief Shane Daw said numbers at the city's beaches were down.

Mr Daw said surf lifesavers had also been affected by the death.

"The tragic event of a young man losing his life in such horrific circumstances obviously creates a number of fears and concerns amongst the public and the lifesaving personnel," he said.

"We are conscious of what we are going into and we know that the chances are very very rare, but ... something like this does bring those fears to the front of your mind."

Despite the government authorising the killing of the shark, normally a protected species, a police spokesman today said police were not actively hunting it as it would be hard to identify the right shark.

Mr Peterson's father Philip has said he does not want the shark killed and that his son had admired and respected sharks.

Philip Peterson also said his son's death should prompt more funding to keep beachgoers safe from sharks.

Mr Daw said surf lifesavers, police and sea rescue had stepped up their patrols this weekend.

Although they were not doing anything out of the usual they had decided to "gear it up a little bit just to make sure we are doing everything we can", he said.

Mr Daw said if a large shark was spotted, swimmers would be alerted and surf lifesavers would use boats to chase it out to sea.

"We use those boats in a herding fashion and sometimes we will bring the helicopter down and use the down-wash to push the shark out to sea and away from people," he said.

- AAP