Sharks unlikely to threaten swimmers says researcher

Sharks are unlikely to threaten swimmers in New Zealand waters says researcher.

Warmer waters have brought more sharks in to shore but seeing one while swimming is no reason to panic, an Auckland University researcher says.

Leigh Marine Lab’s Dr Craig Radford says sharks are unlikely to pose a threat unless you are spearfishing and have just speared a fish.

Last month, Auckland Council website Safeswim.org.nz advised residents not to swim at Omaha and Tawharanui, after shark sightings were reported.

Orewa Beach was closed down on Christmas Eve after lifeguards received reports that a two-metre shark had been seen by swimmers.

“Sharks are more visible in summer, but they are always there. Surfers often see them at Pakiri beach,” Dr Radford says.

“You do need to be smart because they are predators and we are in their environment. But I wouldn’t panic – it’s just a respect thing.”

In 2009, a bronze whaler shark bit a lifeguard’s inflatable rescue boat at Omaha after they tried to scare it away by revving the motor.

Dr Radford says shark sightings are actually positive because they are a sign of a heathy ecosystem.

“They are at the top of the food chain and we need them to eat to keep things under control.”

Dr Radford has been researching how sharks use sound to navigate the ocean and has found they hear at frequencies below 1000 hertz.

For the next phase of his studies, he will be putting sharks into an MRI machine to get a more detailed understanding of how they hear.

The project is a collaboration between the University of Auckland and the University of North Carolina.