Why more sharks are being recorded in Sydney waters this summer

Experts say there are more sharks in Sydney waterways this summer – and one government act is attracting them closer to shore.

Experts have warned of an abundance of sharks in Sydney Harbour and the city’s beaches this summer as several factors and one controversial government policy beckons them closer to shore.

Data from the NSW Department of Primary Industries shows bull sharks routinely travel from vast distances along the coast to spend time in Sydney Harbour over the summer months.

A study of 40 tagged adult bull sharks showed the creatures exhibited “clear seasonal patterns” of movement, travelling into Sydney Harbour during summer and autumn, with their population in the harbour peaking in January and February.

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Bull sharks, along with tiger sharks, are responsible for almost every shark bite countrywide.

A news.com.au analysis of data from NSW’s Shark Smart program showed 23 shark detections at Sydney beaches since the start of the year – 16 detections of bull sharks, and seven detections of tiger sharks.

Bull and tiger sharks, alongside great whites, are among the three “target” shark species responsible for almost every shark bite countrywide.

Research has also shown great white numbers are up, having recovered after earlier being a threatened species.

While the increase in shark numbers in the harbour may be typical for summer, experts warned several factors were attracting the predators closer to shore – including one controversial government act.

A group of teenage fishermen found a surprise at the end of their fishing line over the weekend when they accidentally hooked a bull shark in Sydney Harbour. Picture. Supplied.

Shark nets: a false sense of security

The shark nets relied upon to keep much of Australia’s coastline shark-free provided only a false sense of security, and could even attract the predators closer to shore and swimmers, according to Humane Society International marine biologist Lawrence Chlebeck.

“What we really need is for the government to rely on more effective ways to reduce the risk of shark bite,” Mr Chlebeck told news.com.au.

“The shark nets that we’re relying on this summertime don’t actually reduce the risk of shark encounters. In fact, they can even attract sharks closer to shore due to the animals that get caught in the webbing and die, making for seriously easy bait.”

Mr Chlebeck called for investment in “more scientific methods” like drum lines, personal shark deterrents, drone surveillance and education, if the government is to keep swimmers safe – noting the deadly shark attack in Sydney last year.

Marine biologist Lawrence Chlebeck said shark nets were a false sense of security, and actually beckon sharks closer to shore.

Warmer waters, more sharks

An increase in temperatures was also bringing sharks closer to shore, Mr Chlebeck said.

“As temperatures rise in summer and with climate change, these animals adjust their feeding patterns and move closer to shore,” he said.

“The data doesn’t necessarily indicate a net increase in population size, but it does mean they’re more visible and closer to humans.”

Some of the excess sightings were due to “more eyes on the water” as the government increases its shark watching technologies, and locals get involved, Mr Chlebeck added.

Sydney fisherman James Murray made headlines this week when he, armed with trackers from the DPI, pulled a huge bull shark out of Sydney Harbour, and tagged the monster fish before setting it free.

A Sydney fisherman was met with shock this week after he pulled a huge three-metre bull shark from Sydney Harbour. Picture: Channel 9.

Murky waters favour a shark ambush

Off the back of heavy rains and floods across much of the east coast, experts sounded the alarm that murky water correlated with a greater risk of shark encounters.

The DPI said last year the nutrients washed into the water by heavy rain readily attracted fish and other animals looking to feed and, in turn, attracted sharks.

The reduced visibility of murky water also made conditions ideal for the ambush predators, which could hunt unsuspecting prey without being spotted until the last second, the department said.

Keeping swimmers – and yourself – safe

As the sharks move closer to shore for the summertime, Mr Chlebeck said he didn’t believe there was an “increased risk”.

“There’s obviously a small risk whenever you enter the ocean with shark safety, and there are always things we can do. Things like swimming with a buddy, not swimming in very murky water, not swimming directly inside a ball of bait,” he said.

As long as the government invested in high-tech shark deterrents, and abandoned nets, Mr Chlebeck said he believed swimmers could stay safe.

Wildlife expert Vanessa Pirotta told news.com.au the information gathered by shark watching programs was “extremely valuable”.

“It helps us understand how we can coexist with these animals in one of the busiest harbours in the world,” Dr Pirotta said.