According to research from CSIRO, approximately 8,000 great white sharks roam the waters off Australia.
Using genetic and statistical analysis of DNA extracted from juvenile sharks, the total population estimate included about 2,210 sexually mature adults. Using statistical methods, the researchers were able to estimate how many adults had produced juveniles.
Researchers hail the study, which was published in this month’s Scientific Reports journal, as the most accurate census of adult great whites to date. Previous population studies relied on data obtained through fishing and other sighting reports.
“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,” the CSIRO’s principal research scientist Rich Hillary said in a statement.
“This is crucial to developing effective policy outcomes that balance the sometimes conflicting aims of conservation initiatives and human-shark interaction risk management.”
These numbers only include great white population along the east coast, from southern Victoria state to Central Queensland state and across to New Zealand. A total population estimate on the west coast—from southern Victoria to north-western Western Australia is now underway.
Although more data will be needed to determine trends, research indicates great white populations have stabilized or declined slightly since they became protected in 1999.
“The most we can say at present is that the current estimates of abundance and key demographic parameters (survival, fecundity etc) are more consistent with slight current declines or zero population rate of change,” the report said.
