On Sunday, police in Western Australia called off their search for the body of a 52-year-old surfer, two days after he was seen being attacked by a shark. This puts the year’s shark attack tally at six—the highest number of people killed in unprovoked attacks since 1934.
This number is well above Australia’s 50-year average of 1.02 deaths a year. Yet while fatalities are at an 86-year high, the number of unprovoked shark bites, 17, is more or less in line with the average over the past decade: meaning it’s not the number but rather the nature of the attacks that’s contributing to the uptick in deaths.
“In some of the cases this year it sounds like the shark hung around and bit more than once, which is unusual behaviour for great white sharks,” Dr Blake Chapman, a marine biologist who examined shark neuroscience for her PhD, told Guardian Australia. “[And] when they bite more than once it’s more likely to be fatal as there’s more blood loss.”
Dr Chapman noted that multiple bites could suggest the apex predators are starting to treat humans as prey. Another factor could be the weather.
The Bureau of Meteorology recently declared a La Niña weather event in Australia, which is typically associated with cooler sea surface temperatures in the central Pacific and warmer waters around much of the country’s northern waters. These water temperatures influence the migration patterns of certain fish—like salmon, for example—and so dictate the movement of the sharks that eat them—namely, great whites.
Several of this year’s victims were attacked by great white sharks—and as Dr Chapman points out, “We do tend to see little spikes in shark bites in La Niña.”
She also noted however, that details and data are relatively scarce, making it hard to determine with any real certainty why so many people in Australia have died from shark attacks this year.
In January, an experienced diver was killed by a shark in the waters off Western Australia; in April, a wildlife ranger was killed by one off the Great Barrier Reef. In June, a 60-year-old died from a shark in northern NSW; in July, a teenage surfer died from a shark bite at another beach in the region; and in September, a 46-year-old surfer died after being bitten while surfing near the Gold Coast in Queensland.
However, it’s worth pointing out that just because a lot of people have died this year, it doesn’t mean that shark attacks are on the rise.
As Dr Andrew Chin from James Cook University points out, the number of actual bites is the same as last year and less than 2019. “It’s just that unfortunately the bites this year have led to more fatalities.”