Shark Drum Lines: Do They Work?

When 17 year-old Ballina surfer, Cooper Allen, was attacked by a Great White Shark last week he became the 5th surfer in his local area to be bitten in the last two years (four along the same one kilometre stretch of beach alone). Cooper’s home stretch, which begins at Ballina, runs through Lennox Head and finishes at Byron Bay, is also home to some of the best point breaks and tourist beaches in the world, attracting millions of dollars in tourism revenue each year. The NSW State government is now planning to deploy 100 ‘smart’ drum lines along the NSW North Coast in the coming weeks in a bid to prevent more attacks. 

Do drum lines work? 

The short answer is yes. There is considerable data available on the efficacy of drum lines. The state of Queensland, whose state line begins just 90 minutes north of Ballina, first used the technology in 1962 and has had one fatal shark attack on a controlled beach since (compared with 27 fatal attacks between 1919 and 1961). 

Marine biologist and leading researcher in the field, Professor Colin Buxton of the University of Tasmania, explains: 

“Drum lines have been shown to be effective if used properly because they reduce the number of sharks in an area by killing them.”

Of the pros and cons of using drum lines, Professor Buxton says: 

“The pros are that drum lines kill sharks and thus reduce the number of sharks in an area and this reduces the statistical chance of a shark encounter with humans.”

“The cons are that they kill sharks which has both moral, ethical and biological considerations. People will argue that these animals have a right to exist and are an integral part of the ecosystem which when removed has a flow on effect to other parts of the system.”

How Do They Work?

Drum lines are a pretty basic fishing device involving a large baited hook attached to a rope (or metal trace) which is then attached to a floating buoy, or the seafloor. The shark takes the bait and either dies, or, in the case of the “Smart” drum lines being deployed off the coast of NSW, sends a signal back to authorities who then travel to the buoy to collect the shark and either tow it out to sea or kill it. 

“Drum lines will catch anything that takes the bait, but are probably less indiscriminate than shark nets which will catch things like dolphins, seals, whales, turtles and other charismatic megafauna, as well as smaller harmless sharks and fish,” explains Professor Buxton. 

Why has it taken this long to do something about it?

This is a very good question. Considering the longstanding effectiveness of Queensland’s drum line program in preventing shark attacks, it would have seemed the obvious step for other State governments to take. Instead the State of NSW opted to pour millions of dollars into a failed and since aborted shark net system earlier this year. Fifty four years after Queensland started using drum lines, NSW is finally following suit. 

In Western Australia, a series of fatalities in a short window saw the introduction of a drum line program in January 2014. A group of scientists then made a submission to the local government detailing why the drum lines alone would not be enough to improve ocean safety. They were later withdrawn.

Are the use of drum lines the same as shark culling?

Professor Buxton says, yes. 

“Both have the same outcome. They are intended to lower the numbers of sharks. To be effective though both will need to be sustained in a way that the population remains depressed. By this I mean that going out and killing one shark suspected of biting a surfer is not likely to be a long term solution.”

But aren’t drum lines confined to a single (or series) of popular beaches, with the aim of protecting those specific areas, which would make them less concerned with lowering shark numbers generally as much as lowering shark numbers in the specific area where the drum lines are installed? Whereas culling seems aimed at lowering shark numbers generally…?

“No. The effect of the drum lines will be to depress the local population which will be dependent on the movement rate of the sharks. Large sharks are mobile and most are long-lived and slow growing. So taking out big sharks as they move through the area will have an effect far wider than the location of the drum lines.