SWIMMERS but particularly divers in Yanchep, Two Rocks and Lancelin should know the most northern satellite-linked shark monitoring receiver in the metropolitan area is off the Ocean Reef Marina.
This means there is far less shark sighting information available from the Yanchep, Two Rocks and Lancelin areas.
Department of Primary Industries and Regional Development operations and compliance, sustainability and biosecurity executive director Bruno Mezzatesta said at this stage there were no plans to extend the shark monitoring network to Yanchep, Two Rocks or Lancelin.
So unless you are in the ocean when a helicopter patrol is in the area or in an area where a beach patrol is conducted such as Yanchep Lagoon the McGowan Government would probably recommend people use an independently verified personal shark deterrent for which the government is offering a rebate.
The government has invested more than $33 million in a broad range of shark hazard mitigation strategies, and continues to commit to initiatives such as helicopter and beach patrols, science, education and awareness, emerging technologies and beach enclosures.
Western Australia has a vast coastline and the number of juvenile white sharks – the species responsible for most deaths in Western Australia in the past 17 years – is not yet known but in the past 12 months a total of 19 white sharks have been tagged off the WA coast.
In November and December last year and in February this year 11 female and five male white sharks were tagged at a range of locations near Esperance including Alexander Point, Salisbury Island, Daw Island, Israelite Bay, Cape Pasley, Middle Island and Cape Arid.
In a statement Fisheries Minister Dave Kelly said all 16 white sharks could now be detected if they swam within range of one of the state’s 27 satellite-link shark monitoring receivers.
Mr Mezzatesta said two white sharks were tagged off Fremantle in July 2017 – one measured 3.84m and the other 3.52m.
“Also, a 4.5m white shark was tagged off Mandurah in October 2017,” he said.
Beached or rotting whale carcasses are one of things the department’s team can take advantage of to tag white sharks from the southern-western population, which extends from Victoria, along the South Australian coast as well as WA’s south and west coasts.
“Large aggregations of fish (salmon and snapper) may also provide tagging possibilities and we look for these environmental opportunities, because unlike other parts of Australia there are no known white shark aggregation sites along the WA coast.
The white sharks recently tagged near Esperance ranged in size from 2.8m to 4.6m in length.
Mr Mezzatesta said male white sharks matured at about 3.3m to 3.5m and females at between 4.2m and 4.7m. “
“Only two of the 19 white sharks tagged in the last 12 months were above the generally accepted size at maturity – the 4.5m male tagged off Mandurah in October and a 4.65m female tagged off Alexander Point, east of Esperance in November 2017.’’