We’re not high on bull shark menu
RATHER than being crazed killers as they are sometimes portrayed, bull sharks actively seek to avoid people, a researcher says.
Jonathan Werry, of Ocean and Coast Research, who tracks the bull sharks' movement around south-east Queensland, including Sunshine Coast beaches, said, "If we were on their menu, there would be a lot more people being attacked."
Mr Werry said he had tracked the animals swimming under and around surfers.
He tags sharks with a range of tracking devices and says increases in attacks are dependent on species and conditions.
Rainfall is a key driver of bull shark attacks.
The scientist said that when we received enough rain, plankton blooms occurred at the interface of fresh and salt water.
"It creates a hot spot that draws bull sharks to feed there,'' he said.
"In those conditions, close to a river mouth on the edge of a deep drop-off, there will be an increased chance (of attack).''
Mr Werry is involved in the Large Shark Tagging Program, funded by the State Government.
Acoustic receiver stations to pick up signals from tagged sharks have been located off Caloundra, Mooloolaba, Maroochydore, Coolum and Noosa.
The program has tracked 3.5-metre dusky whalers from off Moreton Bay, past the Sunshine Coast and Fraser Island and up to the southern Great Barrier Reef.
Most track to Fraser Island before heading out to waters that reach 4000m in depth in the South Coral Sea.
He is also waiting for a sophisticated tracking device attached to a four-metre female tiger shark to
begin sending signals.
The pop-off tag records data until it eventually releases from the animal, floats to the surface and begins transmitting data by satellite.
One tiger shark the team has tracked was recorded reaching a depth of 1106m, well below the 680m previously recorded.
The research team is on the verge of launching several websites to better inform the public about sharks and to source funds for further studies.