Following the announcement of a SMART drumline trial set to take place off the coast of Gracetown, we sat down with a SMART drumline researcher in NSW to talk about what they do.
Department of Primary Industries head scientist Paul Butcher runs the SMART drumline trial in NSW and is responsible for the program’s research.
Mr Butcher said there were more than 100 SMART drumlines and research gear in the water as part of six separate trials in six locations.
Currently, 20 SMART drumlines were at Ballina and another 10 at Evans Head as part of an ongoing trial while the other locations had four separate six month trials.
Everyday a team take the drumlines and moorings out of the water so they are not left overnight, and contractors go out each morning and setup the gear between daylight and 8am.
“The contractors have a range of times to take the gear out, obviously the earlier the better because we cover those morning surfers who go before work,” Mr Butcher said.
“Some of our locations have fairly dangerous bars so we need to give some leeway to the contractors to be able to get back out across the bar during the morning and day as well.
“In the afternoon they bring the gear in and we give them a two hour window before sunset.
“The reason for such a big window is they are covering drumlines across a 13 kilometre stretch of coastline which takes an hour to bring all the gear back in.
“If they get a shark or two during that period we need to give them time to be able to tag and deal with the animal before they have to come back across the bar which is far too dangerous after dark.”
Mr Butcher said Ballina had the biggest stretch in the trial which they saw as a maximum for the contractor to be able to respond to a drumline the furthest distance away in poor conditions.
On average they work 22 to 25 days a month and in conditions your average boater would not be out in.Department of Primary Industries head scientist Paul Butcher
The SMART drumlines are setup 500 to 600 metres off the shore break, Mr Butcher said it was hard to tell how many were caught daily or weekly.
In the six different trials, Mr Butcher said they had caught in total 253 white sharks, 39 tiger sharks and 9 bull sharks and 193 by-catch animals across 13 species.
“They are certainly effective for catching white sharks, one thing we will never know is how many are actually swimming past and how many we are actually catching,” he said.
“Just because we caught 253 does not mean twice or ten times as many were swimming past and there has certainly has not been any interaction or a bite with surfers in that period.
“It is a two-pronged approach in that we are catching animals that could possibly interact with surfers but at the same time there are probably other animals that swim past and are not hungry.
“It certainly is not the silver bullet but it is certainly effective for catching white sharks.”
It certainly is not the silver bullet but it is certainly effective for catching white sharks.Department of Primary Industries head scientist Paul Butcher
Mr Butcher said for every shark that was caught a range of biological data was collected including the species, by-catch species, size, sex, lengths and other information.
The researchers also collect genetic samples from the sharks and for some of them they also took blood.
Mr Butcher had a PHD student who was also working on the program looking at a range of factors about the catch ability of drumlines, trace types, hook types and trace materials.
They were also looking at the blood work and the physiological response of white sharks to capture and see what stress was on the animal.
“The contractor might get the shark within five minutes and are able to take blood within five minutes, other times when there are multiple captures it might be 30 minutes to an hour before the animal is attended to,” he said.
Last week, the WA Government announced it would start a trial off Gracetown where two separate shark attacks occurred hours apart on the same day in April this year.
It was announced the government would trial the technology for 12 months to determine if it was effective at reducing shark attacks in WA.
Chief Scientist Peter Klinken will conduct an independent scientific analysis of the trial and the personal shark deterrent subsidy.