Cape Town - If you’re on your way to the beach and want to minimise your chances of an encounter with a great white shark while you’re there – and who doesn’t? – first check the water temperature and the phase of the moon.
According to new research, and based on several hundred observations by the Shark Spotters at Fish Hoek and Muizenberg, white sharks are much more active at new moon – including during the day over this period– and when the surface sea temperature is more than 14°C and heading towards 18°C or warmer.
The authors of the research suggest that these “significant” correlations are most probably because of an increase in the sharks’ natural prey at such times or because they create better hunting conditions for them – not because the sharks prefer warm water.
And they argue that a greater understanding of the behaviour of large, predatory sharks like great whites, bull sharks and tiger sharks can be used to increase the safety of sea users “in a proactive and environmentally friendly way”. The research paper “The influence of environmental variables on the presence of white sharks, Carcharodon carcharias, at two popular Cape Town bathing beaches” is published in the online, open-source research journal PLOS ONE , and the principal author is Kay Weltz of the Marine Research Institute at UCT’s zoology department, who conducted the study as part of her MSc research.
Co-authors are shark specialist Dr Alison Kock, who is the research manager of the Shark Spotters, UCT marine scientists Dr Henning Winker and Dr Colin Attwood, and Shark Spotters manager Monwabisi Sikweyiya.