5500 white sharks lurk off Aust east coast

Breakthrough research by the CSIRO has found that around 5500 great white sharks live off Australia's east coast.

A great white shark in the ocean.

Breakthrough CSIRO research reveals 5500 great white sharks live off Australia's east coast (File). (AAP)

Around 5500 great white sharks are lurking in the waters off Australia's east coast, new research has revealed.

For the first time, the CSIRO was able to put a number on the size of the white shark population using world-first genetic analysis.

The organisation estimates there are about 750 adults in waters off Victoria's southern coast, up to central Queensland and across to New Zealand.

Taking juvenile sharks into account, researchers believe the total east coast population sits at 5460 - but it could be as high as 12,800.

It is estimated another 1460 adult white sharks live off Australia's south-western coast, but a total calculation is yet to be made.

Widespread publicity around shark attacks, particularly off NSW's north coast, often prompts calls for culls, nets and other counter-measures.

But the paper's lead researcher, CSIRO scientist Richard Hillary, said there was no documented evidence backing up a link between attacks and shark numbers.

"We did not look at the risk of shark attacks," he told AAP.

"There is no scientific study I know of people making the link between numbers of sharks and people being attacked by them."

Instead, Dr Hillary hoped state governments would use the information to review the effectiveness of policies around local shark populations.

Until now, it was difficult to gather information about adult white sharks because they wee difficult to sample.

But breakthrough genetic and statistical methods meant scientists could estimate shark numbers without having to catch or even see them, the CSIRO said in a statement on Friday.

"Now that we have a starting point, we can repeat the exercise over time and build a total population trend, to see whether the numbers are going up or down," Dr Hillary said.

"This is crucial to developing effective policy outcomes that balance the sometimes conflicting aims of conservation initiatives and human-shark interaction risk management."

The research found the adult population of white sharks had been essentially flat since the shark became a protected species in the late 1990s.

The impact of these protections wouldn't be seen until the juvenile sharks, born in the intervening decades, reach maturity in the next five to 10 years.

But the data marks the critical first step in documenting a population trend and finding out if white shark numbers are going up or down.

"Balancing the conflicting goals of conservation and human protection is at times difficult and contentious," the researchers wrote on The Conversation.

"But, unquestionably, without being able to monitor populations effectively there is no way to resolve these questions."


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Published 9 February 2018 5:18pm
Source: AAP


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