Beachgoers walk past colour coded shark warning flags, black indicating poor visibilty, on Cape Town's Muizenberg beach, April 25, 2012. Muizeberg lies on the edge of False Bay, home to a large concentration of Great White sharks. A fatal shark attack a week ago has triggered a wave of anger against the practise of chumming, the luring of great white sharks with a smelly mixture of fish and oil by tour operators and researchers, with surfers and swimmers calling for a ban on the practice. REUTERS/Mike Hutchings (SOUTH AFRICA - Tags: ENVIRONMENT TRAVEL)