Shark attack

Shark! Shark!

Shark Attack! Those two small words strike dread into the hearts of those among us who secretly hold the fear of one day becoming the victim of one of the ocean's silent predators.

But what are the realities of the dangers of shark attack in Australia? How many people actually do fall victim, what are the chances of survival once attacked, which species are to blame and importantly, how can we lessen the chances of such a misadventure?

Fortunately, we do have some of the answers to those questions thanks to a comprehensive computer database known as the Australian Shark Attack File (ASAF) held at Taronga Zoo in Sydney, and compiled by shark expert, John West.

John began gathering the data for the ASAF in 1985, and initially drew on existing, but scattered information from earlier scientists including medical Professor Victor Coppleson and Gilbert Whitley of the Australian Museum. He has since tracked down virtually every known incident involving a shark attacking and/or biting a human in Australia, and regularly updates summaries for public release.

The criteria for inclusion in the ASAF are quite clear: Any human/shark interaction where injury occurs to a human, being alive at the time of the attack; the equipment worn or held is damaged (including surfboards and kayaks) or where imminent contact is averted by diversionary action by the victim or others. Criteria include provoked attacks, and attacks on divers feeding captive sharks, but data on incidents involving attacks on boats, dead bodies or animals are not included on the main file.

THE FATAL SHORE
Since the earliest recorded attack in Australia in 1791 (a fatal attack on a native female on the north coast of NSW) there have been 702 recorded cases in Australian waters which fit the above criteria. Of those, 194 (or 27.6 per cent) were fatal.

Which part of Australia is safest from shark attack (apart from the obvious answer - Alice Springs)? Data for each State are shown in the accompanying table and indicate that, perhaps not surprisingly, NSW has recorded the highest number of attacks, closely followed by Queensland, with both States recording the same number of fatal attacks - 73. On the other hand, Victoria, the second most populous State, shows a very low rate of attack and only seven fatalities in 200 years. Both WA and SA have recorded more shark attacks than Victoria, with SA topping the list with respect to the percentage of attacks which have resulted in fatalities. And there is one good reason for this latter statistic. Many of the attacks in SA have been by large white sharks which are responsible for a higher fatality rate than any other species of shark.

RELATIVE RISKS
Statistics can be pretty boring, but to put the chances of shark attack in Australia into perspective, the risk of becoming the next shark attack statistic is far less than succumbing to many other causes of death by misadventure. Remembering that there have been 194 fatalities due to sharks recorded in Australian waters over 220 years of European habitation (less than one per year), it is sobering to note that between 250 and 280 people are drowned every year in Australia. Want more? Well, believe it or not, there are two to three deaths every year in Australia caused by bee stings, and about the same number killed by lightning strikes.

Despite the increased population and probable increase in numbers of people entering the sharks' domain, there has been a significant decline in the rate of shark related fatalities since the 1930s. This is almost certainly due in part to protective meshing of surf beaches (there have been no fatal attacks on a meshed beach since these programs were instituted) but could also be due to a decrease in either the relative, or absolute abundance of sharks themselves. On the other hand, the numbers of all recorded incidents has increased a little over recent years, but perhaps this is because recording of relatively minor incidents is more comprehensive than before.

THE PRIME SUSPECTS
Even though there are more than 350 species of shark worldwide, less than 10 could be considered to pose a serious danger to humans. Certainly, the white shark (otherwise known as the great white) is considered the most lethal, and has been responsible for some recent well publicised fatal attacks in South and Western Australia. The general theory surrounding white shark attacks is that the shark mistakes humans for seals, and while this is quite possible, it still means that this is a shark which should be feared (after all, other species of sharks presumably don't attack humans because they think they know what we are).

Other species of shark which are known to have attacked humans are the tiger, blue and great hammerhead sharks, and importantly, several species of whaler shark, including the bull, bronze, dusky and oceanic whitetip.

Large shark species missing from this list include the mako and porbeagle, and other whalers, such as reef, galapagos and java sharks. All of the latter have the potential to inflict lethal injuries on humans, but positive records of fatal attacks are sketchy.

Of course, proving the culprit in a shark attack is often extremely difficult, so it is possible that some or even all of the above species may have caused fatalities at some stage.

After the white shark, the most dangerous shark is widely considered to be the tiger shark. This large species commonly comes close to shore, and is a true scavenger, eating pretty well whatever it can get its jaws around. Tiger sharks often follow ships which dump food scraps overboard and it is this species which is most commonly associated with attacks on survivors from sunken commercial fishing boats. Having examined the stomachs of many large tiger sharks, this is one species I would not want to share the same part of the ocean with!

The whaler sharks are also considered to be particularly dangerous, and it is members of this family which are responsible for the great majority of attacks within or near the mouths of estuaries, especially after heavy rain when they gather to feed on dead animals and fish flushed out by floods.

The bull shark, Carcharhinus leucas, is one of the prime candidates in this respect, and while juveniles of this species would not be considered as highly dangerous, certainly large specimens have caused many fatalities both here and overseas.

Large blue sharks, great hammerheads and oceanic whitetips have all been implicated in attacks on survivors of plane crashes and ship sinkings. It is presumed that they are attracted to such scenes by debris and blood, and some truly horrific stories have emanated from such incidents.

Looking at the data in the Australian Shark Attack File, the species of sharks responsible have been apparently identified in about 40 per cent of incidents. This amounts to just 13 species, with some unusual inclusions such as wobbegongs (in one incident, a wobbegong swam six metres off the bottom to latch on to the leg of a female diver), seven-gill sharks and even one gummy shark!

However, looking at actual fatalities, the list contracts to the usual suspects noted above: about 46 per cent of all fatalities have been caused by white sharks, followed by tiger sharks (27 per cent) and whalers (26 per cent). And in hindsight, we can be fairly sure that most of the whaler shark fatalities were caused by bull sharks.

OK, so even though shark attacks are very rare, the risk is still there, so it always pays to be aware of what not to do in order to avoid becoming the next statistic.

AVOIDING ATTACKS
Knowing exactly why sharks occasionally attack humans is perhaps the most difficult question to answer. It is generally accepted that the majority of shark attacks are 'accidental', in that the shark mistakes a person for something else.

In the case of white sharks, that something else would likely be a seal, while for the whaler sharks, including the bull shark, flashing white hands or feet in turbid water may be mistaken for a school of prey fish. Tiger sharks, on the other hand, eat just about anything, so to them a person is just another object to investigate - and bite. So with some of this information in mind, what can we do to lessen the already slim chance of attack even further?

Looking at the accompanying list of what not to do, it is best to avoid swimming in areas where there is a lot of baitfish activity and associated predation by seabirds, dolphins and other feeding predatory fish such as tailor, Australian salmon, mackerel and so on. Chances are feeding sharks will also be present, and while they may be more intent on chasing their natural prey, staying well clear is good advice.

Secondly, murky or turbid water inside estuaries is more likely than clear conditions to create confusion for feeding sharks. Such conditions after rain, near the mouths of estuaries and rivers, may be particularly dangerous since sharks are known to be attracted to these sorts of areas after 'freshies' in the system.

Finally, consider the time of day to enter the water, especially if the first two conditions apply. Many fish species feed at dawn and dusk, and there is at least some evidence to suggest that sharks may be especially active at the end of the day, before sunset.

And while all of this advice certainly applies to persons swimming from beaches or the shore, some specifics are also particularly pertinent to boaties.

Lots of boat owners tend to anchor just out from beaches and spend time swimming in the general area. If so, always look before you jump in, don't swim in dirty water, keep an eye out for surface fish activity, and preferably, don't keep spearfishing in the one area. For both short and long stays on anchor, but especially if on the same anchorage over a number of days, always avoid tossing food scraps or cleaning fish overboard. We all know that burley attracts sharks, but sometimes, we just don't consider the consequences of our own actions.

Having outlined these precautions, it should also be realised that there are exceptions to every rule, and that there have indeed been shark attacks in clear water in the middle of the day. Nevertheless, taking at least some preventative measures is certainly a lot better than the cure in the case of our worst nightmare.

And finally, what should one do if attacked? Advice to anyone who does have the awful misfortune to be attacked usually includes whacking the shark on the snout or trying to gouge its eyes. These tactics probably do help, if one was thinking clearly enough, but most survivors of attacks recall dread, fear and panic, rather than rational thought at the time.

The message from this brief look at shark attacks in Australia seems pretty clear. Shark attacks are rare events. In fact, you have far less chance of being bitten by a shark than you do of winning the lottery. Knowing that should help us all to rise above the inevitable hysteria each summer and start thinking of and treating sharks as what they really are. Beautifully adapted apex predators that are an integral and important part of the ecology of the world's oceans. Logical, yes. But one final word: It's always better to be safe than sorry.

HOW NOT TO BECOME A STATISTIC