Researchers at Stellenbosch University have presented the findings from the largest great white shark study done in South Africa and as it stands SA’s great white sharks are heading for extinction if the situation stay the same. The research team estimates that there are only 353 to 522 great white sharks left in South African waters. The six year study also found that the genetic diversity of our great whites is the lowest in the world.
This on the study published in the Marine Ecology Progress journal by Dr Sara Andreotti.
“Using mark-recapture techniques, the results from this part of the study indicate with 95% confidence
a population estimate of between 353 and 522 individuals. According to Andreotti, this is 52% fewer
than what was estimated in previous mark-recapture studies.
However, they needed to be sure that the white sharks that they identified and counted in Gansbaai
were representative of the entire white shark population along the South African coastline. Thus they
set sail again and spent another four years sailing along the coastline, collecting biopsy samples and
photographs of dorsal fins. The subsequent genetic analysis then proved that there is only one
population and that the same sharks are roaming the coastline.
The results from the genetic study show that the South African population of great whites is made up
of an effective population size of only 333 individuals. The effective population size is the number of
individuals in a population who contribute offspring to the next generation.”
The full Stellenbosch University press release can be seen HERE.
The actual published study can be viewed HERE.
Now you know.
[pic via Sara Andreotti @ www.sharkdivingunlimited.com]