There are no reliable estimates of white shark population sizes or trends in Australian waters.
The local abundance of white sharks in shelf and coastal waters varies from season to season and year to year due to variations in shark distribution and movement patterns.
In some years, people in coastal areas will see more sharks than average; in other years, fewer than average sharks will be seen. These variations are due to changes in distribution that are likely to be in response to environmental factors and prey movements and abundance.
To provide the first overall measure of the size of Australia's two white shark populations, CSIRO scientists have developed a new research toolkit that combines tagging, aerial surveys and DNA fingerprinting and advanced statistics.
For Australia’s eastern white shark population, most of the detective work is done and scientists will soon get their first look at DNA fingerprints to see how close to they are to providing a population estimate.
In the west, the challenge is to find nursery areas where these new techniques can be applied. Aerial surveys will be conducted along the South Australian and Western Australian coastline, and white sharks will be fitted with acoustic and satellite tags to locate nursery areas.
Genetic evidence suggests there are two populations of white sharks in Australia:
- an eastern population ranging along the east coast from Tasmania to central Queensland
- a western population ranging from western Victoria to north-western Western Australia.
White sharks in Western Australia are part of a combined South Australian/Western Australian population and travel between western Victorian and north-western Australian waters with possible links to South Africa.