The rise in water temperatures could be a contributing factor to shark sightings, according to a new study.
The NSW Department of Primary Industries (DPI) report, Patterns of Occurrence of Sharks in Sydney Harbour, was compiled over two years and found that when water temperatures rose, the likelihood of capturing a bull shark rose as well.
Dr Leah Gibbs is conducting research into shark hazard management strategies on the east coast as part of the UOW Global Challenges program. She has also conducted research based in Western Australia on the topic.
Dr Gibbs said, as a predatory species, sharks are likely to be affected by ‘marine heat waves’.
“One of the suggestions is that sharks – like all species – move around to find food,” Dr Gibbs said.
“Other hypotheses relate to the timings of animal migration, which is again related to finding food, as well as to breeding cycles.”
In regard to why the study conducted by the DPI found bull sharks specifically were more likely to be caught in warm water, Dr Gibbs said bull sharks were likely to be caught in warm water because they prefer higher temparatures.
Dr Gibbs said the high temperatures of the past summer could be a contributing factor to the occurrences of shark attacks, which has increased since 2014 – according to Taronga Conservation Society Australia statistics.
Several instances of shark sightings in Wollongong alone have been reported this year, with one surfer lucky to survive an attack at Bombo Beach last month.
Dr Gibbs said the risk of shark attack could be reduced by swimming in groups.
“We don’t know the answers yet, but there is a growing number of scholars working on these problems, which has to be a good thing,” Dr Gibbs said.