‘Stay out of Sydney Harbour’: Fears Elizabeth Bay shark attack will start of ‘cluster’ of bites

Summer is “peak season” for sharks in Sydney Harbour. Water temperatures are high, and on hot days baitfish come to the surface to feed. Sharks follow.

Shark experts are warning Sydneysiders to stay out of the Harbour following an attack at Elizabeth Bay, sparking concerns there will now be a “cluster” of bites.

Lauren O’Neill was swimming off a private jetty in the area when she was bitten by what is believed to have been a bull shark, with the species yet to be formally identified.

University of Sydney shark management expert Christopher Pepin-Neff said there are “a lot of bull sharks in Sydney Harbour”, and there is now an elevated risk of further encounters.

“Shark bites often happen in clusters, so we need to be very careful for the rest of the summer,” he said.

“Water temperatures are high, and this is a warning to make sure that we don’t have a cluster.”

A large bull shark caught in Sydney Harbour in 2022. Picture: Tik Tok

The 2.5m bull shark caught at Birchgrove in 2022. Picture: Tik Tok

While there is “no evidence” the population of bull sharks has increased in the Harbour, Dr Pepin-Neff said shark activity is correlated with the number of sunny days there’s been in a row.

“On hot summer days, baitfish come to the surface of the water, and the bull sharks follow,” he said.

“We need to be aware that Sydney Harbour is still the wild, it’s still the ocean. Looks can be deceiving; the Harbour might look placid and domesticated, but it’s not.”

Veteran fisherman Al McGlashan says it’s ‘peak season’ for bull sharks in the harbour.

Queensland-based environmental scientist Dr Daryl McPhee also said Sydneysiders should stay out of the water until advised the Harbour is safe.

“Bull sharks are one of the three large species mostly responsible for serious bites and fatalities, the other two being the white shark and the tiger shark,” Dr McPhee said.

“While the risk of a shark bite is extremely low, I advise people to stay out of Sydney Harbour waters until further notice by the Government.”

HOW MANY SHARKS ARE THERE AND WHERE?

The NSW Department of Primary Industries has been tagging and tracking the movement of bull sharks along the coastline for nearly 15 years, with 264 tagged to date.

Of those, 87 have been captured in Sydney Harbour, and as many as 18 have been seen in the harbour at any one time – though the exact population is unknown.

NSW DPI shark scientist Amy Smoothey said there are two “hotspot locations” in Sydney, the triangle of water between Kirribilli, Garden Island and the Opera House, and up Parramatta River near Glades Bay.

“Bull sharks … have this physiological capability that allows them to swim readily through saltwater, brackish water, and into the freshwater river reaches.

“There have been recent reports of juvenile bull sharks in the Hawkesbury, in lower numbers, but through time and increasing water temperatures, they’re spending a longer time … further south than they were previously.”

‘BIG BUFFET’ FOR BULL SHARKS

Veteran fisherman Al McGlashan said the summer months are “peak season” for bull sharks, which come down from the north to feed on pelagics – surface-dwelling fish like salmon, bonito and mackerel tuna – and “wander off by March”.

The predators are most frequently found “patrolling” the deepest parts of the Harbour, he said, including where the Lane Cove River meets the Harbour, and at the Harbour Bridge.

“Just yesterday we were under the Bridge and a bull shark jumped clean out of the water in front of us,” he said.

However, the fisherman has also observed fewer sharks – and fewer species – than usual, with the Harbour also less “alive with fish”.

“It could be the run-off, could be the increased rubbish and pollution in the Harbour after all the rain, but it could be a natural, seasonal thing,” he said.

Sydney Institute of Marine Science PhD shark tracker Yuri Niella said bull sharks have been tracked travelling from the Great Barrier Reef as far south as Tasmania seeking warmer waters, but they never skip out on a stop-over in Sydney.

“We found that Sydney Harbour is actually a big buffet – they fact they come back here every year is because they know there’s plenty of food,” Dr Niella said.

Despite undertaking the world’s biggest shark tagging project, the exact population of bull sharks is unknown – the maximum number of tagged individuals in Sydney Harbour at one time is 20, with 130 being tracked in total.

During periods of heavy rain, the animals travel upstream to Parramatta, Dr Niella said.

Able to detect the salinity flux in the Harbour, they move into river systems in anticipation of the fish to follow - indicating they may be more intelligent than first believed.

HOW TO STAY SAFE

Bull sharks are a more aggressive species that bite first and ask questions later, experts say, and the only way to avoid them completely is to swim in enclosed areas rather than off boats and jetties.

“We’re in the way, not on the menu,” Dr Pepin-Neff said.

“Bull sharks are biters – they’re in murky water, and if a bull shark bumps into you, it will bite you.”

The highest risk circumstances for bites, he said, are when there’s an increased number of swimmers in the water, and for individuals when they’re “isolated”.

“Most shark bites happen at 2 o’clock in the afternoon – it’s a big of a misnomer that dawn and dusk are the problem times,” Dr Pepin-Neff said.

“Sharks are apex predators, so you always want to present yourself in the most threatening way possible, and swimming alone isn’t doing that.”

They can be a problem, but that’s usually because you’re isolated at that time.

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