The NSW government will install up to 10 catch-and-release drum lines along the Newcastle coast as it weighs up the best way to protect surfers and swimmers from shark attacks.
The SMART drum lines will be positioned about 500 metres off beaches at Stockton, Nobbys, Newcastle, Bar Beach, Dixon Park and Merewether. They consist of two buoys and a satellite-linked communications unit attached to a hook baited with a single mullet.
The Queensland government has been using drum lines to kill sharks since the early 1960s, but the SMART (Shark Management Alert in Real Time) lines are designed to lower the mortality rate of sharks and other marine life.
NSW Primary Industries Minister Niall Blair will be in Newcastle on Monday morning to announce a three-month trial of the technology starting on February 1.
“This is the first time SMART drum lines will be trialed in Newcastle and will add an extra layer of protection to the NSW government’s shark-net program,” Mr Blair said.
“There are no plans to remove nets from Newcastle beaches, however, we want to continue to find ways to reduce the risk to beachgoers right across NSW.”
The drum lines send a signal to a boat crew when a shark gets hooked. The system is designed to allow the contractors to respond within 30 minutes.
If the shark is one of three “target” species deemed a danger to swimmers, white, bull and tiger, it is tagged then released a kilometre offshore. Other marine animals caught on the drum lines are released immediately.
The contractors upload data about catches, including the animals’ species and size, onto the government’s SharkSmart app after they are released.
The government has been trialing up to 35 SMART drum lines off Ballina, Lennox Head and Evans Head for the past two years.
The Department of Primary Industries website says the trial has caught 213 white sharks, 12 tiger sharks and nine bull sharks since December 2016. One of the white sharks died before being released, and another was found dead on Airforce Beach, Evans Head, five days after being released.
The DPI says the north coast drum lines have caught 87 non-targeted animals, mostly hammerhead, blacktip and dusky whaler sharks. All were released alive except a black marlin and a blacktip shark.
A six-month trial at Coffs Harbour caught 16 white, 18 tiger and 18 non-target sharks, and another six-month trial at Forster caught 65 white, two tiger and 17 non-target sharks.
None of the sharks caught in either trial died, and two more trials on the south coast also recorded 100 per cent survival rates.
In terms of protecting animals, the SMART lines compare favourably with the government’s shark-meshing program, which includes 150-metre nets off 14 Newcastle and Central Coast beaches.
The meshing program killed more than half the 228 marine creatures entangled off Newcastle and the Central Coast in the 2017-18 season.
Only 21 of the animals caught were white, tiger or bull sharks.
The data points to SMART drum lines producing a far better outcome for the sharks and the scientists studying them, but so far it is unclear how much protection they provide beachgoers.
The DPI’s director of fisheries research, former University of Newcastle academic Dr Natalie Moltschaniwskyj, said the drum-line trial was part of a five-year, government-sponsored investigation into options for “environmentally friendly ways of managing shark-human interactions”.
“At the end of the day we’ll be able to put all of the technologies on the table, including nets, and be able to provide the pros and the cons for each one of those,” Dr Moltschaniwskyj told the Newcastle Herald on Sunday.
She said it was too early to gauge whether the NSW trial, and similar research under way off Reunion Island in the Indian Ocean, would provide evidence that the drum lines reduced shark attacks.
“The data that we’ve been able to analyse to date … indicates that the white sharks will move away from the beach where they’ve been caught and released from, so they don’t go straight back onto that beach.
“And it looks like they disappear for a couple of months.”
Dr Moltschaniwskyj said shark alerts being posted on social media and an increase in drone and helicopter beach monitoring had created the impression shark numbers were growing, but this was not the case.
“The CSIRO study that was published last year indicates that there’s no evidence for a substantial increase in numbers,” she said.
“Having said that, there’s a lot of people, including recreational and commercial fishers and surfers, saying that they think they’re seeing more white sharks today than they have in the past.
“It’s possible that we’re seeing changes in the way animals are using the marine waters, and so that may explain why people think there’s an increase in numbers, but that’s just a hypothesis.”