Shortcuts / 03 December 2020
Shark Attacks in Australia
This year, there have so far been eight fatalities from shark attacks – the most in nearly a century – and a total of 23 attacks. So with summer upon us, public pressure is mounting to find out why this is the case. In this episode of Squiz Shortcuts, we take a look at Australia’s history of shark attacks, why they seem to be becoming more prevalent, and what experts are suggesting we can do to prevent them.
What do the record say about Australia’s history of shark attacks?
The Australian Shark Attack File, which is kept by researchers at Sydney’s Taronga Conservation Society and has been recording shark attacks since the beginning of British colonisation in 1791. The File has so far recorded more than 1,000 shark attacks in Australia.
Back in the day, so pre 20th century, there was a higher prevalence of fatal shark attacks which has a lot to do with lack of emergency services and developments in medical care. But that’s changed over time, now, most shack attacks are not fatal and death from shark attacks, the mortality rate, hovers around 0.9 – that’s fewer than one person per year.
So why does it feel like we’ve been talking about shark attacks more than usual lately?
You’re not wrong – over the past decade, the number of shark attacks, both fatal and non-fatal, has tripled from an average of 6.5 incidents per year between 1990–2000, to approximately 20 incidents per year.
What do the records show about where shark attacks are occurring?
Throughout history, most have occurred in New South Wales, followed by Queensland. But the majority of fatalities have been recorded in Western Australia – that’s seen it dubbed the shark capital of the world.
But West Australians might dispute that because although they have recorded the most fatalities, that title really belongs to the US. Last year, it recorded 44 shark attacks, though no fatalities, while Oz came in second with 11 recorded incidents. But that comes down to the size of the States’ population, which is significantly larger than ours. And that’s also why there are more recorded attacks in NSW – because it’s the most populated state. The more people in the water, the greater chance of an attack occurring.
So why does WA have more fatal shark attacks than the rest of the world?
Well there’s lots of theories, some of it’s attributed to humpback whale migration patterns in the Indian Ocean, off the WA coastline. Whales are a favourite food of great white sharks, and in recent years, there have been an increasing number of pod strandings in WA waters as the humpbacks make their yearly migration northwards from Antarctica – which could be attracting more sharks. But it’s all really a bit unknown. What experts do agree on is that there’s probably a number of factors at play that mean attacks and fatalities are increasing.
What species of shark tend to be responsible for these attacks?
So there are about 180 species of shark that live in Australian waters, but it’s really only four of them account for the majority of those fatal attacks. That’s the bull shark, tiger shark, oceanic whitetip shark and the great white shark. And as you may have guessed from the names – those guys tend to be a bit more vicious than your average shark. But even they will generally only attack humans if they feel threatened, or they mistake you for a fish or dugong…
So if sharks aren’t all that predatory towards humans, why are fatal shark attacks becoming more prevalent?
A few reasons have been put forward – one is that population point again, So there are more people are heading to our famous beaches every year, both citizens and tourists, and a rise in the popularity of water-based recreational activities. And more people are accessing more of our coast line – most of which is unmanned by lifeguards.
Climate change has been touted as another factor – there are some suggestions that changing weather patterns, sea temperatures, as well as dwindling fish populations in some areas have changed sharks’ feeding habits, and have seen them sometimes swim closer to the shore to feed – and that increases the chance of an encounter with a human. And then there’s La Nina this year, which will bring more rain and potentially flooding which researchers say could draw, bull sharks in particular closer to the shoreline – and closer to surfers and swimmers.
Nut it’s worth noting that while the number of fatal shark attacks has spiked this year, the number of total unprovoked encounters – which is 20 so far – was right on average. And even full blown shark experts like those who manage the Australian Shark Attack File says that there’s a good chance the increase in fatal attacks might just be a case of “bad luck”.
Is there any pattern to why these fatal shark attacks are occurring?
No, it’s actually quite random. There are many instances where sharks are in the same area as a human and they do not interact with them. And the reason a shark attacks is all still theory – it could be hungry, could be curious, could mistake a person for a seal, or whale, and then there’s the ‘rogue’ shark theory that some are just well… rogue. But few are considered valid. All in all though there doesn’t appear to be a common motivating factor involved in all shark encounters because each shark/human interaction is unique and behavioural and environmental circumstances are different in every case.
So what are some of the preventative measures being taken to reduce the number of shark attacks in Oz?
The debate on how to prevent shark attacks goes way back into the last century, with the practice of shark netting being introduced in 1937. It’s used differently in each state, but basically what happens is submerged fishing nets are suspended – but they don’t go to the seabed, but rather are usually about 6 metres deep… they’re effectiveness is hotly debated… and a study from last year published by the University of Wollongong said nets were largely ineffective for preventing shark attacks, and in fact were more destructive, largely trapping other marine life instead, including protected species.
This had led to many calling for shark netting programs to be replaced with what they’re calling SMART – Shark Management Alert in Real Time – drumlines. They attract a shark with bait and then when a shark takes the bait and puts pressure on the line, a magnet is released and alerts authorities that it is there. Once alerted, the team responds immediately (within 30 minutes) to tag and release the shark or other marine animal… the idea is it keeps sharks away from the shoreline and put them further back out to sea, away from humans. The SMART drumlines are relatively new and are still in the trial phase in both WA and NSW, as is the use of drones which are manned by lifeguards to monitor beaches and spot sharks, and then alert beachgoers.
Another strategy is tagging. Since the late 80s, Aussie researchers have been tagging dozens of great white sharks to get a sense of their patterns of movement, with satellite tagging taking off in the early 2000s. So when a tagged shark approaches the coastline, it alerts authorities, who can then close nearby beaches or warn people away. The introduction of tagging has helped researchers get a better idea of where sharks tend to congregate, but not why. And of course, it hasn’t seemed to prevent shark attacks.
And then of course there’s the every man for himself approach where you can by shark-proof wetsuits, watches, and surfboards. And in Western Australia for example the government is on board with this and offers resident a $200 rebate if they buy an approved personal shark deterrent device.
This also plays into an argument many make that in order for humans and sharks to live harmoniously, human behaviour needs to change. They argue that humans are technically encroaching on the shark’s habitat, rather than vice versa, and that educating surfers and swimmers is the key. And there’s plenty of government resources out there on how to keep yourself safe… for example, swimming in groups, and not going in the water at dawn or dusk when there’s a greater risk of an attack.
But shark attacks are pretty inevitable, so what happens after one occurs?
Usually authorities will search for and kill the shark responsible, in order to prevent any further attacks. But sometimes the shark gets away. And in some cases, like in WA, authorities have undertaken shark culling – or the mass killing of sharks – as a preventative measure against attacks. But animal rights and conservation groups criticise the practice of pre-emptive culling, and say it’s more driven by emotion rather than science.
Are sharks populations in Australia under threat?
According to the Taronga Conservation Society… Shark populations are generally considered to be in steep decline in Australia and around the world due to overfishing. One cause is the high price obtained for shark fins in Asia, known as finning, a practise that is now widely banned. Having said that, outfits like the Taronga say it’s really hard to know the true number of sharks in our oceans.
And as far as the arguments some have made to say that because we are protecting shark in our oceans, thats ha lead to increase in attacks, there is not much merit in that and there really is no scientific evidence that indicates a substantial increase in the numbers for those species.
Why do hammerhead sharks look like that? – BBC Earth
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