Barriers that prevent sharks from entering sheltered water could be tested under State Government plans that have all but given up on the idea of netting Perth's most popular swimming beaches.
As a report found that shark nets killed too much marine life and did not safeguard swimmers, it emerged the Government was considering installing enclosures somewhere along the Swan River.
The Government is also believed to be eyeing a regional location, such as Geographe Bay near Busselton. But the measures, which have not been costed or given a timeframe, would be limited to areas of protected water because the enclosures are typically too weak to withstand ocean swells.
The limitation means anti-shark enclosures would be unsuitable for Perth's most popular swimming beaches such as Cottesloe and Scarborough, which are regularly battered by winter storms.
Fisheries Minister Norman Moore said the Government was receptive to the idea of enclosures.
But Mr Moore noted that they would be of narrow use and would not have prevented any of the recent shark attacks that have killed five people and injured several others in the past year.
Instead, Mr Moore said the Government was also investigating whether to empower the Fisheries Department to kill sharks before they attacked anybody if the risk was deemed high enough.
And he said the Government could be willing to provide more money to researchers at the University of WA amid hopes they can develop effective shark deterrents for ocean users including divers and surfers.
The Government-commissioned report, conducted by Bond University researcher Daryl McPhee, found the environmental and financial cost of shark nets outweighed any benefits.
"There is no silver bullet," Mr Moore said. "If you look at the attacks we have had, the most recent one was north of Carnarvon.
"I don't know what the Government could do in terms of putting nets in that location.
"We need to try to look at as many options as we can to minimise the risk."
Cottesloe mayor Kevin Morgan dismissed the idea, saying any shark enclosures would quickly become very crowded and could become a risk in their own right.
Shadow treasurer Ben Wyatt said the Government was dragging its heels and should decide on a strategy to reduce the risk of shark attacks before summer.
"I just can't understand what the delay is," Mr Wyatt said.
"Make a decision and do it."
'We need to try to look at as many options as we can to minimise the risk.'" Fisheries Minister *Norman Moore *