What the numbers say about the risk of shark attack
A fatal shark attack in WA on Saturday has generated worldwide media coverage on the dangers of Australia's waters -- but statistics indicate those risks may have been overstated, write Cathy Alexander and Leigh Josey.
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A fatal shark attack in Western Australia on Saturday has generated worldwide media coverage on the dangers of Australia’s waters — but statistically, you’re more likely to die falling from a chair or accidentally cutting yourself on broken glass than in a shark attack.
Surfer Ben Linden is believed to have been taken by a great white shark near Wedge Island, north of Perth. His death is the fifth fatal shark attack in Australia in 10 months — an unusually high toll.
The story has been picked up around the globe — from The Sun and The Mirror in Britain, to NPR and CBS News in the US.
The death of Linden, and the four other men who have been killed by sharks in the past year, are tragedies that have shaken the surfing community in particular. The apparently increasing rate of shark attacks clearly justifies the current debate on safety in WA waters.
But does the extensive media coverage accurately portray the risk? Just how dangerous are sharks?
A sample of some of the headlines from Australia and overseas covering the latest shark fatality
Between zero and five people are killed in Australia by sharks each year. Taronga Zoo maintains an Australian Shark Attack File, which puts the total at 217 fatal shark attacks since European settlement. The average over the past 20 years is 1.1 deaths per year (this figure excludes shark attacks that are considered “provoked”, e.g. deaths during spear fishing, although there are few of these).
According to the most recent data from the Australian Bureau of Statistics, which covers deaths registered in 2010, there were just over 140,000 deaths in Australia that year.
In 2010, four of those deaths were due to “contact with a marine animal” (although it appears not all of those animals were sharks; another shark tally found there was one shark death in that year). This compares with 1484 deaths in transport accidents, and 864 deaths due to accidental poisoning. Obesity was responsible for 221 deaths, while assaults claimed 217 lives.
More people died from falling from a ladder (27 deaths) or drowned in an accident involving a water craft (24) or a swimming pool (22) than died in shark attacks. Similarly, swine flu (19 deaths) had a higher toll than sharks, while 14 died in falls involving a chair, and five died as a result of accidental contact with broken glass. Being bitten or struck by a dog claimed four lives — the same number as those killed by marine animals.
Taronga’s Shark Attack File notes that deaths due to shark attacks are “extremely low” compared to other deaths from water-based activities, such as beach drownings.
“People should be more concerned with swimming at a beach than being killed in a shark attack,” John West, manager of life sciences operations with the Taronga Conservation Society Australia, told Crikey.
There may have been plenty of media attention on shark attacks but that doesn’t seem to have translated into research on sharks, their movements and why they attack.
Kent Stannard, a shark-tagger, surfer and founder of White Tag (which aims to track and understand great white sharks) says studies into marine environments are atrociously funded and that more research into the behavior of west coast great whites is needed.
“There has been some limited tagging and research done in WA but it has few known sites of seasonal white shark aggregation and these are mainly in the southern ocean where there are seal colonies,” Stannard said. “Up the west coast, there are no seal breeding colonies, just a couple of haul-out sites which makes locating sharks difficult and time-consuming, hence expensive.”
Great whites are “actively mobile”, says Stannard and, as a migratory species, may be more predatory when on the move than when residing temporarily near seal colonies.
“Nobody really knows why great whites attack,” he told Crikey. “They are completely misunderstood. They are highly intelligent and, contrary to popular belief, quite shy.”
Stannard keeps track of sharks by the use of either satellite or acoustic tags attached to the dorsal fin, under the skin or, in the case of juvenile great whites, the stomach lining. The tags help plot the highways and movement patterns of the animals. His research has found sharks can return to a particular location each season.