By: Rigardt Hoffman (M.Sc. Student, University of KwaZulu-Natal)

Diving With Raggies: Hobby Or Harmful?

The research entails looking at the interactions between the ragged tooth shark (Carcharias taurus) and the recreational SCUBA diver at the Aliwal Shoal Marine Protected Area. Ragged toothed sharks are listed as vulnerable (IUCN red list) and the behaviours of recreational divers may alter the breeding behaviour and ultimately endanger the population. A code of conduct has been developed for divers and diving operators regarding diver behaviour that should be obeyed when encountering these animals. However, no South African studies have attempted to investigate whether divers adhere to these prescripts, nor whether the protocols are optimal for sharks at this site. The particular study site at Aliwal Shoal is the Cathedral dive site, which is a very popular dome like cave that the sharks use for refugia in the process of breeding. Being visited by hundreds of divers each year, we have no idea whether this negatively affects the sharks at all.

This study aims to video the behaviours of divers and the reactions of the ragged tooth shark population to see the effect that the divers have on the sharks. The diver behaviour can possibly alter the mechanics of a population and could impact individual sharks behaviour. Examples of this may be chasing them away from preferred refugia, which may be less conductive to mating behaviour and also make them more susceptible to predation by Great White Sharks (Carcharodon carcharias) and Tiger Sharks (Galeocerdo cuvier). The outcome of this work should contribute to a better understanding of the existing dive protocols and whether this needs improvement to minimize the impact of scuba divers on the vulnerable ragged tooth shark.