Great White Sharks are not only creatures of grace and beauty in their natural habitat, they are also critical to the health of our oceans.
- As apex predators, they help to regulate the balance of marine ecosystems by feeding on the animals below them in the food chain.
- Great White Sharks naturally feed on the weakest specimens first – thus ensuring survival of the fittest.
- They also feed on the carcasses of whales and other large marine creatures, which could otherwise pollute the sea.
But these enigmatic predators have fallen prey themselves – to the stereotype of a man-eating monster and to the steadily rising threats of detrimental nets and drumlines, bycatch and depleted food due to commercial fishing, shark finning and poaching. Together, these practices kill up to 100 million sharks a year.
SharkCageDive.com is not just a Shark Cage Diving operation. We are passionate about the protecting endangered sharks and involved in facilitating and funding several ocean conservation initiatives. These include:
- Our Conservation Volunteer Programme – this offers you the chance to study Great White Shark behaviour in one of the world’s most fascinating and dynamic ecosystems. It also offers you to cage dive with Great White Sharks at least once a week while on the programme and to contribute to ocean conservation, as well gather much-needed research data about these endangered sea creatures.
- The Sharksafe Barrier – an innovative new technology to promote beachgoer safety without costing the lives of marine creatures.
- Identification and Genetic Shark Research spearheaded by the University of Stellenbosch, aimed at proving demographic information about Great White Sharks.
By cage diving with SharkCageDive.com, you are helping to support these groundbreaking Marine Conservation Projects and protect the great white shark and our environment.
The Sharksafe Barrier
The Sharksafe Barrier is a non-lethal alternative to the shark nets and baited drumlines that prove lethal to thousands of sharks, dolphins, turtles and other species every year.
Scary stat: It has been reported that in the KZN shark barrier alone, over 1 000 Great White Sharks have died due to nets and baited drumlines since 1978, as well as over 1 500 tiger sharks, 6 500 hammerhead sharks, 25 whale sharks, and 1 500 manta rays (Peschak 2009).
The Sharksafe Barrier is the collective brainchild of Dr. Craig O’Connell from the US, Mike Rutzen, a local conservationist, Dr Sara Andreotti from Italy, Prof Conrad Matthee of Stellenbosch University.
Craig O’Connell began investigating whether sharks would avoid large magnets while doing his PhD at the University of Massachusetts Dartmouth. He believed they would be, due to minute pores located around the nose and eyes of sharks and rays known as the Ampullae of Lorenzini, which contain a gel sensitive to magnetic/electric fields. This electrosensory tool enables sharks to sense the electrical field of their prey, even in low visibility.
O’Connell’s research showed that when sharks where confronted with a food source between two sets of poles – one attached to strong magnets and another without magnets – the sharks avoided each of the poled areas roughly the same amount of the time, always opting to find a route free of poles to access the food source instead.
On a trip to South Africa, O’Connell met Prof Conrad Matthee and Sara Andreotti from Stellenbosch University, and Mike Rutzen, a local conservationist, and the team collaborated to take his work a step further. During countless hours spent observing sharks in their natural habitat, Rutzen had noticed that Great Whites tended to avoid entering kelp beds. Combining the theories based on this observation and O’Connell’s research, the team came up with the Sharksafe Barrier – a structure made from pipes that emit a magnetic force and that looks like a kelp bed. The team have been working the Sharksafe Barrier since 2011, and it is currently in its final phase of testing. Sharkcagedive.com is helping to fund this Ocean Conservation Project through the sale of buffs, the establishment of a volunteer programme and other initiatives.
It has been shown to be effective at deterring sharks and holds great promise as a technology to promote beachgoer safety as non-lethal alternative to detrimental nets and drumlines.
Identification
The identification and tracking of Great White Sharks is crucial to understanding more about these mysterious marine sea creatures and the role they play in marine ecosystems. Dorsal fin identification is one of the main methods of keeping track of great white sharks, but until recently, it had roughly an 85% error rate.
This high error rate was linked to three main issues:
- Photographs not taken straight on
- Water droplets, shadows or sunlight obscuring part of the fin
- The use of a facial recognition programme to process fins in the absence of a tailor-made one.
SharkCageDive.com has supported Rutzen and Dr Andreotti’s development of ‘barcode’ identification system to provide more accurate and reliable information about sharks. This method involved splitting images of fins into three sections, so that if one section is unclear, the other two can still be matched.
By matching fins manually using this system, Dr Andreotti built a database of dorsal fins over time that covers approximately 98% of the Great White Sharks visiting the waters of Gansbaai. From this, we can deduce that the same sharks come back to the area time and again.
Genetic Research: DNA Sampling Program
SharkCageDive.com supports the collection of DNA samples spearheaded by the Department of Environmental Affairs and Stellenbosch University, aimed at collection much-needed information about Great White Sharks. It is hoped that the DNA testing, together with photo identification, will reveal if the Great White Sharks in South Africa form one isolated genetic pool or if they are linked with other populations overseas. (More info coming soon…)
