The behaviour of sharks in waters off Tasmania should not be regarded as unusual or indicative of an increase in shark numbers, a marine scientist has said.
Dr Russ Bradford, senior experimental scientist at the CSIRO’s oceans and atmosphere branch, said there were many previous examples of interactions similar to those seen in recent weeks.
The CSIRO, or the Commonwealth Scientific and Industrial Research Organisation, is the federal government agency responsible for scientific research.
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“White sharks are inquisitive animals that investigate all sorts of things as they move through their environment,” Dr Bradford said.
“To say that they will not approach a boat is wrong – especially when that boat is sitting off a known seal haulout.
“There have been many recorded interactions with white sharks and boats around the world.”
Dr Bradford said the recent interactions, including the attack in which a 10-year-old boy was dragged from a boat off Stanley, coincided with reports of increased marine activity – such as seals and whales – in the area.
“With respect to the two most recent Tasmanian encounters with white sharks it was noted that there was a lot of marine life in the area at the time,” Dr Bradford said.
“Sharks of all types are well attuned to their environment and it is not unexpected that there would be sharks in the area at that time.
“Two sightings within a short period of time, with one being at a known seal haulout is not an indication of increased shark numbers.”
Dr Bradford also said the observed increased in shark numbers may also be explained by more humans in a position of observation.
“White shark observations in Tasmanian waters are sporadic and highly dependent on the type of activity being undertaken and where.
“For example, abalone divers are more likely to report seeing a white shark than a recreational fisher.
“Yes, there is more boat activity and more people are equipped with cameras and devices to quickly share information about sightings.
“I would say the sharks are not behaving unusually.”
Stanley angler Bernard Atkins speculated in July that sharks may be attracted to the local seal population.
In June, Parks and Wildlife Service biologist Dr Kris Carlyon spoke about two whale beachings in the Circular Head area, which he said may indicate a healthy whale population and successful breeding season.