Late whale season to blame for spate of shark attacks?
A BALLINA resident and former professional diver has hatched a new theory explaining the spate of great white shark attacks this year - and when the sharks are more likely to strike again.
Nick Brennan, who has a background in marine science, has dubbed his theory the "hungry shark theory".
He theorises that an unusually late whale migration season had forced some great whites to go hungry and find different sources of protein.
"My belief is the whales being late and potentially more clustered together has resulted in less feeding opportunities for a portion of the white shark population at a key time," Mr Brennan explained.
"My thoughts are that a portion of the population hasn't fulfilled their need for calories and thus are heading close to shore to feed on schooling fish like the Australian salmon."
The other aspect to Mr Brennan's theory is the timing of shark attacks, which according to records of recent encounters are clustered around the full moon, as opposed to the new moon.
Mr Brennan's explanation for this is twofold - one that full moon tides are more dynamic, with bigger highs and lower lows, and according to the old fisherman's saying 'no run, no fun' they create more feeding opportunities for predators.
Second, unlike other sharks, great whites have "extremely good eyesight", using it to identify and hunt their prey.
"As the full moon approaches there is light after sunset and white sharks are perhaps approaching a time where they are peaked up to get their calories," Mr Brennan speculated.
This is contrary to other sharks such as bulls and tigers, which are more typically known to enjoy low light conditions around the new moon and poor water visibility as a competitive advantage to stalk prey.
The theory would also explain why the two fatal and two serious attacks since September last year - all attributed to great whites - took place in almost perfect water conditions and sunshine.
Supporting this, the majority of documented great white attacks in Western Australia, South Australia and South Africa have occurred in clear water.
Such attacks have thrown the general theory that shark attacks usually happen in low light and murky water conditions.
Mr Brennan said his theory was purely speculative and "never meant to be a conclusion" although he was glad it was firing debate.
"I wrote it... to remind people that white sharks are a creature dictated by their biology and their surrounds and are in a struggle just like the rest of us," he said.
"The good news is I don't believe this will last."