Large, predatory sharks can affect prey populations in two primary ways. They can directly influence the densities of their prey, or they can indirectly influence prey behaviour. Both ways can have important impacts on populations and ecosystems. This research aims to better understand why sharks are important to our coastal ecosystems.
WHAT WE’VE LEARNT SO FAR
White sharks have a significant effect on Cape fur seal behaviour, influencing seal movement in time and space.
- De Vos, A., O’Riain, M.J., Kock, A.A. and Meyer, M.A. (2015). Behavior of Cape fur seals (Arctocephalus pusillus pusillus) in response to spatial variation in white shark (Carcharodon carcharias) predation risk. Marine Mammal Science.
- De Vos, A., O’Riain, M.J., Meyer, M.A., Kotze, G.P. and Kock, A.A. (2015). Behavior of Cape fur seals, (Arctocephalus pusillus pusillus) in relation to temporal variation in predation risk by white sharks, (Carcharodon carcharias) at a seal rookery in False Bay, South Africa. Marine Mammal Science.
- Laroche, R.K., Kock, A.A., Dill, L.M. and Oosthuizen, W.H. (2008). A predator-prey game between sharks and two age classes of seals. Animal Behaviour. Vol. 76: 1901-1917
Although dusky sharks (Carcharhinus obscurus) primarily eat fish, they are opportunistic and formidable predators capable of killing vulnerable whale calves.
- Dicken, M., Kock, A.A. and Hardenberg, M. (2015). First observations of dusky shark (Carcharhinus obscurus) predation on a humpback whale (Megaptera novaeangliae) calf. Marine and Freshwater Research.
Sevengill sharks in False Bay have been found to occupy a higher trophic level than white sharks.
- An investigation into the trophic dynamics of the broadnose sevengill shark (Notorynchus cepedianus) in False Bay, South Africa using multiple tissue stable isotope analysis. (See “What’s on the Menu for Sevengill Sharks” under our “Research Highlights”)