Drumlines catching sharks and protecting surfers
A six-month trial of SMART (Shark Management Alert in Real Time) drumlines along the New South Wales Mid North Coast has shown the devices are "removing the threat of great white sharks from popular beaches" and protecting swimmers, researchers say.
In August the Department of Primary Industries (DPI) deployed 20 devices in two areas including beaches at Forster and Tuncurry and also further north around Coffs Harbour and Sawtell.
The DPI said a total of 64 sharks were caught off Forster and Tuncurry during the trial, with as many as 16 great white sharks over two metres snagged on devices there in just the first month alone.
Researcher Paul Butcher from the DPI's Fisheries Conservation Unit said the latest data from the trial showed the devices were effective in reducing the threat of an interaction between the sharks and swimmers, by effectively removing target sharks that came too close.
"It can reduce the likelihood of an attack or incident with a dangerous shark," he said. "We are catching animals on those beaches that are being used by the public and after capture and tagging they're nearly 15 to 20 kilometres offshore in the next two days.
"But at the same time we're getting that scientific data to tell us where they are on those beaches and when they're moving along our coastline."
Mr Butcher said there was a good reason to explain the high number of great white sharks caught off Forster and Tuncurry compared to Coffs Harbour and other parts of the coast.
"In the Port Stephens Hawkes Nest area we know there's a juvenile nursery area for great white sharks and basically that Forster area is an extension of that nursery," he said.
In contrast Coffs Harbour's catch was far less, with only 15 sharks caught during the trial.
A whale and sharks swim through a baitball at Tuncurry, September 2017
Forster local and surfboard designer Jada McNeil said it was apparent there were more sharks and described a recent close call she had at popular One Mile Beach with her daughter.
"As the wave formed in front of me it was like looking into an aquarium," she said. "We were diving right into it, and my reaction was to get my daughter out as quickly as possible.
"We were actually shocked that it was captured on film, no-one else had seen it, but it was certainly there."
Ms McNeil says the latest trial data showing the large number of sharks being caught on drumlines was disconcerting but not enough to stop her from going for a swim at her beautiful local beach.
"It is causing a bit of hysteria, and I think a lot of people have the attitude that they would rather not know," she said. "It is affecting the surf tourism industry and affecting beachgoers as well."
Ms McNeil said she was also concerned that the baited drumlines, which were positioned about 500 metres offshore during the trial, were deployed too close to swimmers and surfers and potentially attracting sharks to their vicinity.
The smart drumline uses GPS to send real time alerts to Department of Primary Industries scientists and contractors
SMART drumlines differ from traditional drumlines because they are able to alert operators when a shark has been snagged on a baited hook, and the aim is for a team to reach the animal as quickly as possible to increase its chances of survival.
"We're tagging the animal when it comes up to the surface and then we can track that animal for over a period of 10 years," Mr Butcher said. "That scientific data tells us they're moving up and down our coastline."
Mr Butcher said the data so far disproved previous theories that sharks became localised in areas like Ballina and Evans Head where spates of attacks had occurred over the past two years. He said the data showed that the sharks preferred to stay in deeper waters once they were caught and generally stayed away from the area they were caught, with most continuing their movement up and down the coast.
"The data shows they move far up into Queensland, around Rockhampton, to New Zealand and down into Tasmania and Victoria with some animals travelling to Western Australia," Mr Butcher said.
As part of the State Government's Shark Management Strategy SMART drumlines are just one of a number of mitigation measures being explored. A recent report into the trial of shark nets from November between Lennox and Evans Head showed as many as 24 animal deaths, with a single bull shark caught off Ballina the only target species captured.
In contrast the death of only one animal in the SMART drumlines trial has led Greens MP Justin Field to label shark nets an "abysmal failure".
"The nets on the north coast, and there's 50 across Sydney beaches, do not catch many target sharks, but they do catch non-threatening species including turtles and dolphins, which often die," he said. "They kill hundreds of marine animals and there's whales that die too."
Mr Field said the SMART drumline trial data was promising, but he said a broader strategy was required.
"This can't be the only strategy, a big part of the strategy has to be surveillance and drone technology. Increasing resources for surf lifesaving and professional patrols is one of the most effective ways to improve safety," he said.
"But this evidence coming in from the tagging trial has been really valuable to give communities an understanding of how sharks behave and where they're located around the NSW coast."
© Australian Broadcasting Corporation. All rights reserved.