Dolphins were seen swimming in the Swan River on Saturday moments before a Perth teenager was killed by a shark. She had reportedly jumped into the water to swim with them.
Due to a common belief that they chase sharks away, many Australians were shocked to hear 16-year-old Stella Berry was attacked close to the pod of dolphins.
But that's actually an "urban myth" according to Bond University’s Associate Professor Daryl McPhee, who warns some shark species even feed on dolphins.
Before the Swan River attack, there were reports of prey species including tailors and herring in the water. Dr Leonardo Guida from the Australian Marine Conservation Society said both dolphins and bull sharks could have been simultaneously chasing them for feed. “It's basically the ocean and a river system working as it should. And tragically it appears that the young woman may have just been in the wrong place at the wrong time, which makes it all the more tragic,” he said.
Are shark sightings increasing?
While there are more reports of shark sightings, there is no evidence that shark numbers are increasing. Many sharks and ray species have actually decreased by 70 per cent over the last 50 years.
It is possible some shark species could be lured to new territories as a result of climate change warming southern waters. The same phenomenon could also be influencing the distribution of some jellyfish and sea slug species.
Assoc Prof McPhee believes there are two key reasons behind the surging shark reports, the first being changes in media distribution. “If we look at Reunion island, that little French-speaking territory in the Indian Ocean, before the 24-hour, social media, news cycle we wouldn’t really have got much information about what’s happening there at all,” he said. “But when there's a shark bite there it’s in our news, my news feed on the Gold Coast and lots of other people's instantly,” he said.
The other measure driving increased shark reports is that humans are getting better at spotting them, and then using devices to capture and share images. “When I was spending a lot of time fishing in remote places in the late eighties and early nineties, I was seeing lots of shark activity up close that would have been YouTube gold these days, but we didn’t have smartphones then,” he said.
Are most shark bites fatal?
It’s important to remember that there are more than 1000 species of shark, and most interactions with humans do not have a negative outcome. Fatalities are rare and usually only involve only white, bull and tiger sharks.
The majority of the world’s shark bites occur in Florida and mostly involve small sharks. “Although painful, the injuries require no more than a few stitches,” Assoc Prof McPhee said. “We’re talking about bites on ankles and calves.”
“In Australia, most shark bites do not result in serious injuries, but unfortunately, very sadly, some do result in fatalities,” he added.
On the east coast, several Sydney beaches, including the iconic Bondi and Bronte, were shut down last February after a swimmer was killed in a shark attack at nearby Little Bay, the first such fatality at the city's beaches in nearly 60 years.
Australia ranked behind only the United States in the number of unprovoked shark bites on humans in 2021, according to the University of Florida's International Shark Attack File.
with Tara Meakins and Reuters
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