A search of the days turned up the man’s surfboard, but his body was not found. This year Australia was the victim of Australia’s seventh shark attack – a worrying spike that has not been seen in the country for 86 years.
“Australia has been a bit blizzard in Australia (this year),” said Kulum Brown, a professor in the Department of Biological Sciences at McQuery University in Sydney. “And in fact the long-term average is one – one casualty per year. So seven is a long way over it, no doubt about it.”
An average of one death per year has been stable for the last 500 years, a Teronga spokesman said.
It’s not that there has been a sharp increase in shark attacks in Australia as a whole – there have been 21 shark incidents this year, which is normal and consistent with previous years. The difference is in mortality.
There are numerous possible explanations – many experts have pointed out that year-on-year statistics fluctuate, and this can be easy luck. But there is another potential culprit: the climate crisis.
As the oceans heat up, entire ecosystems are being destroyed and forced to adapt. The fish are migrating where they have never been before. The behavior of the species varies. And, as the marine world changes, sharks are following their prey and moving closer to shore popular among humans.
Global Australia is an attractive destination for global warming
On land, Australia’s climate crisis has led to bush fires, extreme heatwaves and record droughts.
The Great Barrier Reef, a living marine ecosystem along the east coast, has experienced such widespread repetitive bleaching that more than half of the corals on the reef have died. Huge poplars of mangrove forests have also died in the last decade.
“Those two ecosystems alone are responsible for the vast diversity of marine ecosystems – so you see huge ecosystems disappearing and / or moving on,” Brown said.
Such “coastal tropical whales” often travel up and down the coast, Brown said, riding the eastern Australian Australian current featured in the movie “Finding Nemo.” But now, climate change means winter is warm enough for these fish to survive the season – so some species are choosing to live permanently in southern waters.
“I spend a lot of time boating on the coast and this year I don’t remember a year where I collected a lot of bait fish around the shore,” Brown said. Researchers still can’t be sure exactly what drives the movements of many of these species – but Brown added, “There’s no doubt that sharks are only responding to bait fish there.”
Sharks follow water temperatures
The ocean is by no means a static mass; Rising currents mean there are areas of hot and cold water. The Eastern Australian Streets current is a big player in this dynamic – it has become even stronger in recent decades, meaning it is pumping warmer tropical water off the coast.
But as the current intensifies, it pushes some eastward shores towards cold nutrient-rich waters.
This dynamic, migrating water temperature is probably why sharks are starting to move into human spaces. Some species, such as bull sharks, like warm water – so they spend more time in warm southern waters, said Robert Harcourt, a researcher at shark ecology and director of the marine predatory research group at McQuery.
Meanwhile, species like the great whites that prefer lower temperatures come closer to shore where even cold water pockets have abundant prey. Tiger sharks are also more commonly seen in the north – but have descended as far as Sydney, which is probably also influenced by the current.
These three species – the bull, the great white and the hairy shark – are responsible for most of the shark attack deaths in Australia.
“I know there’s going to be a big movement in many of these species, an increase in geographic range.” “This is because the dynamics of climate change mean that their proper habitat also changes in terms of water temperature and prey distribution. And these animals are large, distant high punishers.”
He added, “They will be in more contact with potential people, and at the same time, human use at sea is increasing all the time,” he added.
There are other possible factors as well
Harcourt said modern technology, improved medical care and faster emergency response times mean shark attack mortality has dropped significantly over the past decade – which is why this year’s spike is a “real discrepancy”.
But apart from climate change, there may be other factors as well. Luck is a big part: in recent years there have been many close calls where the victim was rescued because there was no medical worker nearby, Brown said.
“We’ve managed to rescue some people over the last few years, just to deal with the trauma on an immediate basis because of someone’s merit on the spot, and that will make a huge difference,” he added.
It also depends on where the victim is. “One centimeter from the left if you bite on the foot, and you could die in at least a second or minute,” Harcourt said. “You know, a centimeter to the right, you get a terrible scar and a lot of pain but if you don’t go into shock you have a good chance of survival.”
“Maybe people are spending more time in the water this year because of the current hot weather conditions in Australia,” the court said, or they could increase the likelihood. Run into the shark.
We are in a new era of unreliability
Brown and Harcourt warned that the 2020 mortality rate for shark attacks is based on one-year data only; Given that shark figures can fluctuate year-over-year, it’s hard to say whether the weather reversal is directly causing the spike this year. It can be a simple matter of bad luck; We don’t know for a few years down the line, if we have enough data to determine whether we are in a train or an outlet.
But both experts agreed on one thing: the sea is changing, and so are the sharks. Climate change has wreaked havoc on the world’s natural environment and disrupted how marine ecosystems live, move and potentially interact with humans.
“You can’t draw any conclusions about anything based on (just one year), but there’s no doubt that we’re going through a very, very short period of time,” Brown said.
“All the old distributions of the species and how we interact with them – you can throw it out the window. Whatever comes in the future will be new.”