Wanted: Help with great white shark sightings

A research project is currently underway at Stellenbosch University to gather information about great white sharks along the South African coastline. (Photo: Sara Andreotti)

Stellenbosch University researchers are asking the help of the South African public to report any sightings of great white sharks – especially if they see one of these iconic sea creatures in the cold West Coast waters.

Researchers will use the detailed geographic information being collected on the whereabouts of great white sharks (Charcharodon carcharias) to establish their population size and family history in South African waters. A photo identification database is also being built up to “fingerprint” individual animals. The data will help to secure the conservation of great white sharks worldwide.

The research is done by Ms Sara Andreotti, an Italian marine biologist who is working towards her doctoral degree in zoology at Stellenbosch University, under the supervision of Prof Conrad Matthee and Dr Sophie von der Heyden of the SU Department of Botany and Zoology. Her project on the behaviour and genetic structure of these sharks is conducted in collaboration with scientists of the Oceans and Coast division of the Department of Environmental Affairs.

Great white sharks are known to be migratory, yet very little information about their dispersal along the South African coastline is available. Recent studies along the country’s East Coast and in the Southern Cape waters show that False Bay, Gansbaai, Mossel Bay, Struisbaai, Kleinbaai and Mandela Bay are great white shark “hot spots”, and that individuals regularly travel between these areas.

Recent studies have shown that the marks (or cuts) on the rear of the dorsal fin of a great white shark can persist for at least 22 years, and that these are very reliable visible identification markers. (Photo: Sara Andreotti)

“No one really knows the stability of the ‘hot spots’ where they frequently occur,” says Ms Andreotti. “Therefore we want to extend our knowledge on this cryptic subject by individually identifying specific sharks through our photo databank, and by using genetic tools.”

For the next month (mid Feb to mid March) Ms Andreotti and her co-workers will be sailing on a yacht, the Catalyst, to look for new “shark hot spots” and to photograph great white sharks.

The Catalyst, a 38 foot catamaran, has been kindly provided to the Stellenbosch University research team by Mr Michael Rutzen, a well-known white shark conservationist and cage diving operator who has already supported several research endeavours in co-operation with Oceans and Coasts. His expertise will greatly enhance the team’s ability to find new elusive hiding places of great white sharks.

“Our investigations are complicated by the fact that we do not yet know all the important areas along the South African coastline to go and look for great white sharks,” says Prof Conrad Matthee, an evolutionary geneticist from Stellenbosch University who is co-supervising Ms Andreotti’s research. “The sharks are commonly sighted at Gansbaai, Mossel Bay and Struisbaai, and in Algoa Bay and False Bay, but we are particularly keen to get information on sharks outside of these ‘hot spot’ areas.”

Because very little is as yet known about great white sharks living in the colder waters of the West Coast towards Namibia, the Catalyst will be doing specific reconnaissance work in this area from time to time during the next year.

Prof Matthee has called on members of the public, such as fishermen and recreational boaters to contact the research team should they spot a great white shark in the coming year. “We would especially like to hear about sightings along the West Coast,” he says.

“It will be extremely helpful if they can contact us immediately, with GPS coordinates of the location and the time of the sighting,” Prof Matthee urges. “Real time information can assist us greatly, because with the new vessel, we can fairly quickly get to the location to collect the much needed data.”

Sara Andreotti, an Italian marine biologist studying at Stellenbosch University,is driving the research project on great white sharks. It has received support by white shark conservationist and cage diving operator Mike Rutzen, who has provided a catamaran to sail on. (Photo: Gotz Froeschke)

Ms Andreotti believes that the photographic database that is being built up of all great white sharks spotted along the South African coastline will help to comprehensively study the ecology, movement and life history of individual members of this species. Similar photo banks are also available for southern right whales, for instance.

Recent studies have shown that the marks (or cuts) on the rear of the dorsal fin of a great white shark can persist for at least 22 years, and that these are very reliable visible identification markers.

“These markings are almost like the individual ‘fingerprints’ of each shark,” says Ms Andreotti. “By combining photographic information with genetic data, we will be able to make solid and consistent identification of individual sharks.”

“Such accuracy is extremely important for researchers who are doing population monitoring, who are checking genetic diversity, or who are comparing South African great white sharks to others found across the world,” she says.

“The lack of basic information on this vulnerable species is arguably one of the biggest obstacles in their conservation,” Ms Andreotti explains what drives her study. “A more comprehensive grasp of their population dynamics will help us to develop an adequate long term conservation strategy.”

People who want to report great white shark sightings along the South African coast can contact Ms Andreotti on +27 723 219 198 or Mr Rutzen on +27 823 223 745. Photographs can be sent to sara@sun.ac.za. Visit www.sun.ac.za/botzoo/andreotti for more information.

Take note:

  • Permits and ethical approval to do the research have been received from the Department of Environmental Affairs and the Department of Agriculture, Forestry and Fisheries.
  • Great white sharks are listed for protection under the Convention on International Trade in Endangered Species (CITES) and the Convention for Migratory Species (CMS). The International Union for Conservation of Nature (IUCN) recognises great white sharks as particularly vulnerable due to rapid stock declines. Legislation bans the catch of white sharks and trade in their body parts (such as fins, skin, jaws, flesh) in South Africa, Namibia, Australia, Malta, California and the Atlantic States of the USA.

 For media enquiries:

Engela Duvenage, Media: Faculty of Science, Stellenbosch University, South Africa +27 21 808 2684 science@sun.ac.za +27 82 874 1291.