Sunday, 6 January 2013
Two shark attacks already in NSW so far this summer. Is there any science behind shark myths? Luke Allan lost a finger and suffered a thigh wound when he was attacked while surfing near Port Macquarie on December 28. Two days later, life guard Danny Sheather narrowly escaped when a shark left a 30cm bite mark his surfboard at Dee Why.
Check shark myths
THEY BITE ONCE AND THEN LET GO:
The "one bite" mantra - that sharks make a taste test before moving on is a favourite. But Luke Allan was bitten three times and Glen Folkard suffered a sustained attack at Redhead Beach, Newcastle last year. Attacks by mature great whites can feature repeated bites.
DOLPHINS MEAN NO SHARKS:
Not true. Dolphins will confront sharks when they threaten a member of the pod. But it's much more common for sharks and dolphins to feed together - often they hunt the same prey. Dolphins may be a sign sharks are present rather than a comforting bodyguard.
BLACK WETSUITS MAKE SURFERS LOOK LIKE SEALS
"That is bollocks," CSIRO great white shark expert Dr Barry Bruce says. "The typical white shark you will find in the surf zone in NSW is 2.5m or below. White sharks feed on seals for only a very small part of the year and it does not become part of their diet until the shark is at least 3m long."
In 2009 there were three serious attacks in Sydney in three weeks. Five people died in 10 months in WA last year. Clusters do happen.
SYDNEY HARBOUR IS A SHARK HOTSPOT:
The attack on navy diver Paul de Gelder in February 2009 focused attention on the waterway. The last fatal harbour attack was in 1963.
DON'T SWIM AT DAWN OR DUSK:
Dr Bruce is sceptical about the theory that the risk of attack increases at dawn and dusk.
SHARK NETS MEAN I'M SAFE:
In the NSW shark meshing program, nets are moved among popular beaches. But several recent attacks have happened while the nets were in place. The nets aren't a barrier across the entire beach, but a series of smaller nets in strategic locations.
SWIMMING DOGS ATTRACT SHARKS:
Dr Peddemors said: "There is not one recorded instance of dogs swimming with people and a dog rather than the person has been attacked."
CERTAIN COLOURS ATTRACT SHARKS:
A US Navy report from the 1970s found "a standard yellow life vest occupied by a child dummy was repeatedly attacked by blue sharks. This led to surfers and divers coining the term "yummy yellow". Professor Nathan Hart from the University of Western Australia found sharks had only one type of "cone cell" responsible for colour vision and are unlikely to be able to perceive a multicoloured world. Sharks are attracted to high contrast rather than colours.
URINE ATTRACTS SHARKS:
Despite many surfers now declining a morning coffee before hitting the waves, there's no evidence peeing makes you a more likely target.