Murky warm water, full beaches a ‘perfect storm’ for shark attack

1 month ago 9

By Saturday afternoon, the rain had set in and the Sydney catchment was soaked. Heavy storms dumped 35 milometres over Parramatta in half an hour, filling the creeks and bays that feed Sydney harbour and coastal beaches with a turbid brown run-off.

For shark risk, says Professor Culum Brown, a specialist in fish behaviour at Macquarie University, it was a perfect storm.

A man was attacked and critically injured in Manly near the North Steyne Surf Life Saving Club on Monday.

Sydney’s water was now warm enough for bull sharks, which are drawn to the region in the summer months, as were swimmers escaping warm and humid weather. The run-off had stirred up nutrients and bait fish, and it had flushed bull sharks from the rivers and estuaries into the harbour, foreshores and breaches.

Bull sharks, explains Marcel Green, who leads the NSW Department of Primary Industries shark program, are opportunistic ambush predators. They do well in rivers and bays and at dusk and dawn when low visibility presents them with an advantage over their prey.

By the weekend, these were the conditions that extended up and down the coast, all through the day.

At 4.20pm on Sunday afternoon, a 12-year-old boy who jumped off rocks at Nielsen Park was attacked and critically injured by what was thought to be a bull shark. The rain and unstable weather continued.

Just before midday on Monday, an 11-year-old surfing at Dee Why was battered by a shark that took a chunk out of his surfboard in an attack that matches the opportunistic feeding behaviour of a bull shark. He was uninjured.

Around six hours later, another strike. A man in his 20s, also surfing, was attacked and critically injured in Manly near the North Steyne Surf Life Saving Club. Again, it is thought a bull shark struck in murky water.

On Tuesday morning came a fourth strike – at10am at Point Plomer Beach in Limeburners Creek National Park, north of Port Macquarie. A 39-year-old surfer was taken Kempsey Hospital.

According to Agriculture Minister Tara Moriarty, who is responsible for the state government’s shark mitigation program, such a spate of attacks was unprecedented in Sydney. Speaking on ABC radio on Tuesday morning, she urged swimmers to keep out of the water after rain.

It will be of little reassurance to those who have been scarred or scared over recent days that shark attacks remain so rare that even this spate of attacks remains a statistical “blip”, in the words of Brown.

“It is the nature of the noise in this data set,” he said. “We also have long spells with no bites and or deaths, but the media and society don’t notice those gaps.”

That might be the case, but the number of people killed by sharks in Australia has been growing over recent years. To November last year, the Australian Shark Incident Database had recorded 56 deaths by shark bite since 2000. At the time, the database was yet to include the deaths of Mercury Psillakis, 57, who was killed by a white shark at Dee Why in Sydney in September last year, and a woman killed at Crowdy Bay in the NSW mid-north coast in November by a bull shark.

The vast majority of deaths were caused by white sharks.

In the decade from 2000 to 2009, 14 people died around Australia from being bitten by a shark, the shark incident database shows. From 2010 to 2019, there were 21 deaths. And in the third decade of the 21st century, the tally has hit 23 after less than five years.

Surfers paddle out in memory of shark attack victim Mercury Psillakis.

As Brown explained at the time, the increase in attacks is not due to an increase in shark numbers so much as of human populations on the coast.

“It’s not the number of sharks that’s going up – it’s environmental changes and increases in the number of people engaging in water sports. With climate change, you can swim off Sydney pretty much all year round now, so there are more people in the water. Everyone has a wetsuit.”

Green concurs, pointing out the 305 or so smart drumlines regularly deployed in NSW to catch potentially dangerous sharks – white, bulls and tigers – have detected no increase in numbers.

But climate is having an impact. As Australian waters warm, the range of bull and tiger sharks is extended south, and the period during which bull sharks are active around Sydney is growing longer. Animals that once lingered in waters around Sydney mostly during January and February are now arriving sooner and departing later.

Either way, Green says that in his 25 years of shark management, he can recall no other spate of attacks like the one just seen in NSW.

Be the first to know when major news happens. Sign up for breaking news alerts on email or turn on notifications in the app.