Perth’s four most-used beaches ” Cottesloe, Port, Scarborough and Mullaloo ” missed out on a firm recommendation after a report into a test of shark nets in Dunsborough last summer.
The September report suggested 22 possible WA sites for enclosures. It identified Mullaloo, with up to 20,000 swimmers on a summer’s day, Cottesloe (11,000), Fremantle’s Port Beach (9900) and Scarborough (9000) as WA’s busiest beaches.
Report author and Hydrobiology WA manager Phil Whittle said Cottesloe received significant swell in winter so an enclosure would be damaged if left out, although it could be put out in summer.
Mr Whittle said the list, which featured only Cottesloe from the busiest beaches, was not a ranking and was derived from analysing wave frequency, tide height and beach use for sites.
He said Scarborough had potentially damaging surf and the beach dropped away significantly, while Mullaloo was not included because the list was not ‘exhaustive’.
Bathers and South beaches at Fremantle, Yanchep Lagoon, Safety Bay and Mandurah Marina breakwater had good suitability for enclosures.
Mr Whittle said the report, being considered by the Government, found the 300m by 100m net installed in the shallow waters of Dunsborough was easily installed and removed, did not collect weeds, and could be cleaned.
However, problems with drilling piles securing the structure had added to an initial $200,000 estimated cost and $50,000 may be needed for annual maintenance.
Mr Whittle said stingrays and dangerous fish were trapped by the enclosure that was fixed with weights at the net’s bottom and tied to the piles.
Mr Whittle has rejected Surf Lifesaving WA criticism that enclosures are dangerous for surfers and jet-skiers, saying those water users already faced and coped with current navigation hazards.
‘We wouldn’t be expecting surfers to ride waves through the enclosures, anyway,’ he said.