Getting your teeth into the Great White debate
As we crest over the worst of winter and start looking forward to spring and warmer weather, a tricky question sits waiting on the horizon.
How do you solve a problem like shark attacks? Or, more to the point, is there one? There are more of us in the water than ever before. Are there more of them? And is that why WA has suffered through an horrific 10 months, with five fatal attacks?
West Australian fisheries officers and federal environment authorities met last week to discuss conducting research on great white shark numbers, to see whether the species was still vulnerable and, if not, whether it still needed the protected status it was granted in 1999.
It’s a worthwhile exercise, if for no other reason than it adds to our flimsy knowledge of this migratory species.
But in an environment where most people are inclined to argue that the beasts should be respected and left alone in their native habitat, any proposed change to its status is sure to spark debate if not outrage.
The big and controversial question is whether putting great whites back on the menu, so to speak, can prevent similar numbers of attacks. Arguably, not.
To put the debate in context, WA has had 19 fatal shark attacks since records began in 1791. Three occurred last year, so almost half of them in the past two years, which has understandably left the state reeling and searching for answers. But it seems unlikely, given what slow breeders white sharks are, that the recent surge in attacks can be due to a sudden population boom. (As an aside, SA has also had 19 fatalities, all by great whites, the most recent in February last year.)
Taronga Zoo keeps a shark attack file which shows there is an average of about one deadly shark attack a year, somewhere in Australian waters. So years might pass without incident and then, other years - like the past one - it seems as though the water is a hot zone of predators.
I had occasion to speak to two of Australia’s top shark researchers, Barry Bruce and Charlie Huveneers, for a feature published earlier this year on “the secret life of sharks”. A few things became abundantly clear during the interviews; one of them was how little we know about the habits of these elusive, nomadic creatures.
We know that noticeably greater numbers head up the east coast to the Great Barrier Reef in autumn and winter, or hang around the Neptune Islands off Port Lincoln in winter and spring, or follow migrating whales up the West Australian coast in spring.
But, as the winter attack on young Perth surfer Ben Linden showed, they are everywhere in Australian waters at any one time, from beach shallows to deep ocean, and they don’t stay anywhere very long.
That’s why trying to find and kill a shark after an attack is almost pointless; it might remain in the area for a few days (and even then, how to know you have the culprit?) or it can be 70-80km away a day later.
We can surmise, but we don’t really understand why they attack, or how and why they select particular victims over others, and why sometimes they’ll go for the kill and other times they’ll sail past without incident.
Unpredictable creatures, these.
Which means trying to do a head count is no simple task.
If we’re looking at whether shark numbers are up, what is the baseline given they don’t respect state - or even international - borders?
And how do we know that any supposed increase in numbers is due to a population boom of these coast-hugging animals, and not - to hazard some reasons - because they are aggregating on warmer sea currents or some El Nino-induced factor, or changes in available fish stocks?
That is, is we find numbers are up, can we be confident it’s an absolute and not circumstantial?
If we get the maths wrong, remove the protection and then find numbers plummeting, what then?
It would take decades to repair overzealous culling. White sharks are extremely slow breeders compared to most of sea world - a small litter of pups every three years at most, and only when the females are 15 to 20 years old - so maintaining a population equilibrium (whatever authorities decide that should be) would be a challenging task.
Some people would probably shrug their shoulders and think, ‘so what, the oceans are safer without them’, but you can’t remove an apex predator without everything down the food chain falling out of whack.
Whatever you think of its merits, the task WA wants to take on is perhaps not as straight-forward as it might seem.
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