CSIRO study into shark numbers

HOW WAS THE STUDY CONDUCTED?

* Researchers took tissue samples from living and dead juvenile sharks and compared their DNA to find if they shared a parent

* Using the number of half-siblings, reproduction rates and juvenile survival rates, researchers could estimate the total adult shark population

* The number of sharks in WA could not be calculated as not enough juvenile sharks have been tagged to estimate survival rates

WHAT WERE THE KEY FINDINGS?

* Australia has two white shark populations: The eastern population ranges east of Wilsons Promontory in Victoria, to central Queensland and across to New Zealand; the southern-western population ranges west of Wilsons Promontory to north-western WA

* There are about 750 adults in the eastern Australasian white shark population, with a range between 470 and 1030

* The total number of white sharks in the eastern population is 5460, with a potential range between 2909 and 12,802

* There are about 1460 adults in the southern-western population, with a range of 760 and 2250, but the total population could not be calculated

* Adult survival rates are estimated to be above 90 per cent

* Adult populations are estimated to be stable since white sharks became protected in the 1990s.

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