New research studying the behaviour of Port Jackson sharks has led researchers to investigate if tantalising, but not giving food to great white sharks for tourism purposes, could make great white sharks less likely to reappear.
The study, published in the journal Animal Behaviour, revealed the sharks' interest in the smell of food declined if they were not sufficiently rewarded by the promise of eating.
The observation suggests that sharks learn to avoid wasting time and energy on inaccessible food sources.
The researchers, including lead author Dennis Heinrich from Flinders University, said the results were a catalyst for discovering sharks' evolutionary ability to learn.
Shark ecologist Charlie Huveneers, from the Southern Shark Ecology Group at Flinders University, said the research observed how three separate groups of Port Jackson sharks in captivity reacted when being exposed to the smell of a prey species.
"The group of sharks that was always rewarded [with food] quickly learnt the task and became better and faster at reaching the target," Professor Huveneers said.
"That learnt response was drastically reduced in the group that wasn't rewarded as frequently.
Baiting sharks for tourism ventures
Professor Huveneers said tourism operators needed to find the right balance when trying to attract sharks to an area for the shark cage diving industry.
"They would have to be minimising any kind of association of learnt behaviour, but also making sure they can still attract the sharks using smell for example, because if there's no reward whatsoever then there won't be any attraction after a certain amount of time," he said.
The researchers will now test their findings with shark species that are more commonly targeted by wildlife tourism, such as great white sharks, to determine if shark habits can be detected at tourism locations such as Port Lincoln.
Calypso Star on the Eyre Peninsula is the only one-day shark cage diving operator permitted to use berley to attract great whites, a technique that is controversial in the community.
Researchers have started collecting data on great white sharks, using acoustic tracking to study their residency and their relationship with boats.
Andrew Wright, co-owner and operator of Calypso Shark Charters in Port Lincoln, said habituation "probably rings true" but there are already strict regulations in place for operators that have evolved over the past five years.
"When a shark takes the bait or contacts the cage, we can't put any bait or berley in the water for 15 minutes.
"We have to report that on a daily basis [and] there's checks and balances in place to ensure operators are doing the same thing."
Mr Wright also said that the Neptune Islands, where shark cage operators go, is home to more than 30,000 long nose fur seals so food sources are already plentiful.
"It will certainly be very interesting to see if [the study] turns on everyone's head, the whole thought that shark diving is a negative sort of thing and that it actually attracts sharks to an area … it will be interesting if once and for all we can refute that."
