AN AUSTRALIAN GUIDE TO SURFING WITH SHARKS
Written by Madison Stewart with the help of many amazing scientists, oceanographers and badass ocean goers.
I looked on the surf life saving website not too long ago, it contained warnings of jelly fish, rips and skin cancer... I saw no mention of sharks. It’s become apparent to me that we as a country have no desire to face the reality of the apex predators we share the ocean with until it is too late, and then we talk about them in media stories of fear and terror. In the absence of knowledge and education, how can we expect to co-exist with what is, in reality, a dangerous animal? No cull or net will ever keep us 100% safe on our vast coastline, we will never rid the oceans of sharks, we cannot choose whether or not we interact with sharks, we can however choose the terms on which those interactions occur. This is my small - and I feel much-needed guide - for the people and surfers of Australia who are on the front line of shark interactions daily. You are in situations more dangerous than people like myself who base their work around diving with sharks ever are. You deserve to be flooded with information that may help you, also take responsibility to ensure that when you enter the ocean it is with the most educated approach towards its dangers. Sharks exist in our waters, and it’s not only our job to co exist with them, it’s our privilege, and I truly hope this document helps you do that. I hope this sheds some light on the seemingly endless darkness inspired by the Australian media towards the true risk of a shark attack. According to the Australian Shark Attack File run by the Taronga Zoo, in the last 50 years there have been 47 unprovoked shark attack fatalities. The Royal Life Saving Society notes a 10 year average of 292 deaths per year for people drowning in Australia. There were 176 diving related deaths in Australia between 2002-2009, an average of 23 per year. Fatalities from shark attacks over the last 50 years average just under one per year (0.9).
WHY DO SHARKS ATTACK HUMANS
WHY SHARK NETS AND CULLS ARE NOT THE ANSWER
SHARKS AND BLOOD
SHARK AND YOU
HAVE SHARK POPULATIONS BOOMED?
SHARK MITIGATION DEVICES
ENVIRONMENTAL FACTORS THAT INCREASE SHARK PRESENCE:
Rainfall & River mouths
Drop offs & deep water
Whale carcasses & other animal remains Time of day
INTRO Environmental factors that can affect a white shark’s ability to successfully detect and approach its prey have been researched. Focusing on 8-year period at Seal Island, South Africa, attacks on seals and success rates were noted. Attacks and attempts varied with changes in depth, natural light, time of day, time of year, wind direction and other factors. I once heard someone say there are no dangerous sharks, just dangerous situations, and the same can be true for many animals. There are environmental conditions that can often facilitate the success rate of a shark’s attack, making certain times and features of the environment favorable to sharks, and increase the danger. The following are examples. The reality is that you may avoid all the listed below and surf in crystal clear water at a perfect time on a perfect day and still become subject to a shark attack. Nothing is bullet proof, and taking that risk is something you need to be mentally prepared for before entering the water.
BAIT BALLS Bait balls are a common occurrence along our coastline here in Australia. When small fish swarm in a tightly packed formation it’s usually a defensive measure against predators and feeding frenzies are often trigged by bait balls. I shared an interesting conversation with a fisheries officer once that brought this to my attention. One of the theories for the frequent attacks that occurred in a short span of time in Ballina could be pinned to a single environmental anomaly allowing for masses of bait balls. In the year 2000 we saw the fish species the blue pilchard devastated by a foreign disease introduced into our domestic waters, the blue pilchard was not expected to bounce back from the collapse. The bait balls in Ballina at the time of the frequent shark attacks were made up of the blue pilchard. When a fish species bounces back from something like that they come in an unsustainable proportion, and will usually take time to dwindle down to the sustainable amount depending on predation and availability of food in their environment. So not only did we have bait balls, but an unusual amount of one particular species that was returning in great numbers, meaning the availability of food could have been responsible for the unusual number of sharks in the area, leading to the number of attacks. Flocks of diving sea birds are a good indicator that there is a bait ball offshore, and it is important to look for this and try to avoid surfing any patch of coast where this feeding action may be happening. Putting yourself into a bait ball is putting yourself into a feed frenzy where animals are moving fast and making snap judgments and are in the area to hunt. In addition to these signs be aware that contrary to popular belief large sharks are not deterred by dolphins. In fact dolphins and large sharks will often feed on the same fish and in some cases dolphins are potential food for large sharks.
RAIN FALL AND RIVER MOUTHS These can be dangerous when surfing for a number of reasons. After rainfall, nutrients run into the ocean and bring up fish and other animals to feed, and this in turn brings in different species of sharks. In addition to this the visibility of the water after rainfall can greatly decrease, which is ideal for ambush predators like sharks to hunt in. One example of rainfall creating a dangerous situation was an attack in Ballina, where a man was surfing at 6:30pm near a river mouth after heavy rainfall and was attacked by a bull shark. The rainfall and visibility and also time of day were things that made it dangerous to surf. Bull sharks are the primary concern with rainfall. Being one of the few species that can travel into fresh water by increasing the level of urea in their system, as they mature, research found that bull sharks move down into the lower realms of rivers before migrating to the open ocean in their fifth or sixth year. Dr Jonathan Werry from the Ocean and Coast Research group says "They'll move into beach areas, they get flushed out (of rivers) because their normal distribution patterns rely on salinity levels, that's when you've seen attacks in Australia and around the world; a lot of them have to do with periods of rainfall. You seem them also go into holes within the canals and river systems to possibly get some refuge from strong flowing amounts of rain.” Big enough rainfall will change the normal distribution patterns of bull sharks within a river system and will move bulls out of a river system into a near shore beach area. River mouths also represent a food source for sharks with all run off flowing into the ocean from upriver, things like fertilizers and even sewage can cause fish to feed and congregate in the river mouth area.
DROP OFFS AND DEEP WATER These are opportunities for sharks, and large sharks like to hunt near drop-offs, in-between sand banks and on the edge of kelp forests where they wait to surprise seals, fish or turtles swimming through. The reason great white sharks have a white belly but a darker coloration to the top of their body is so that they remain camouflaged with the ocean ground when looking down, and blend in with the sky when looking up from underneath. Seals and other large mammal prey are fast and can easily out maneuver great whites. This is why great whites attack in a way that has the element of surprise, using their habitat to their advantage. This is why locations where there is a vast amount of deep space underneath can be dangerous if a great white shark is hunting in the area. The depth allows them to complete the ambush foundation of their hunting. Even though sharks are capable of swimming in very shallow water, most shark activity is in deeper water. Shark Spotters in False Bay record over 70% of great white shark sightings behind the surf zone, in deeper water.
WATER TEMPERATURE One example of this is northern NSW, winter is a time when whales are swimming up the coast with their new born babies, and Great Whites take this opportunity and follow the whales and prey on the sick, young and weak. University of Sydney lecturer Chris Neff said every deadly attack in WA had occurred in temperatures ranging between 18 and 20 degrees. “White sharks come in shore when the water surface temperature is about 18 degrees, and there hasn’t been an attack in WA when the temperature wasn’t 20 or below,”. Cold-water upwelling’s carrying nutrients and allowing great whites to push furthest inshore could be the sole factor for grouped shark attacks in WA. Great white sharks are a cold water species, and their bodies possess a counter current artery and vein system, which means a countercurrent blood flow exchanges heat, by mixing the cold blood from the arteries with the warm blood from the veins. Great White sharks can therefore elevate their body temperatures up to 14 degrees higher than the surrounding water. Increasingly warm waters around the globe due to climate change and El Niño can also effect sharks, it’s suggested to have led to the highest number of shark attacks ever recorded in 2015, this is due to greater interactions between humans and sharks in the water, and temperature changes allowing sharks to coexist in closer proximity to humans.
Research has predicated that the E.A.C will strengthen in the future with a changing climate. This will extend warm waters further south and change the tropical and subtropical environments and marine habitats, so you can expect to witness the change. Yes you will see more sharks
- Malia Rouïllon, Physical Oceanographer
WHALES CARCUSES AND ANIMAL REMAINS are an obvious reason for sharks to be present, an easy food source is the goal of such predators, there is even theories that suggest great whites sharks mate when congregated around a whale carcass. The part that is not obvious is the potential source of shark attractants. When we decide to go into the ocean we accept the boat traffic and fishing boats but don’t stop to think about the smells they put through the water for a shark to follow to that area. Sharks strongest sense is smell, but human impact on the environment has meant more things are attracting sharks. 50 shark deaths have been recorded in NSW waters, half of them, occurred in Sydney Harbour between 1852 and 1915 when the Glebe Island abattoir was in operation. Stimuli, like spear fishing, dead whales, or anything else that represents food to sharks is carried with a tide from the area you are about to surf need to be taken into consideration. Human blood is not a major factor that attracts sharks (which is discussed further in this document). Fishing harbors, and areas used regularly by fishermen should be avoided, especially when fish catches are high. Be aware of any whales that have been buried on nearby beaches or may have recently died in the area. There is no for sure way to establish a ‘safe distance’ in-between you and the remains, tides and currents carry the smell.
TIME OF DAY is a factor in shark attacks... dusk and dawn being high danger times dues to the position of light. Dusk and dawn present the most high-risk times, great white hunting habits that have been documented showing that they are at a visual and tactical advantage at times of low light such as dawn and dusk, it makes it easier (harder?) for the seal to spot their camouflage making it ideal for them to hunt. In addition to this they found that great whites continued to hunt throughout the day when it was overcast. Dusk is also a time when fish are up to feed triggering feeding frenzies. As for the risk of being attacked at nighttime, white sharks possess a duplex retina with a low rod– cone ratio suggesting they are diurnal hunters. Other species of sharks, tiger sharks attack at night. Dr Jonathan Werry, a Shark Research Scientist who tracked bull sharks on the gold coast claims that "Dusk, dawn and during the night the shark's movement increases significantly.
Shark attacks occur all year round in Australian waters. Over the past 20 years, 71% of the attacks occurred between November and April. This seasonal peak period coincides with warmest air and water temperatures and school holiday, Christmas, New Year and Easter holiday periods. This is the time of maximal use of beaches, harbours and rivers for recreation, and the time when most people are in the water, increasing the risk of a shark encounter.
- Changing patterns of shark attacks in Australian waters
John G. West, Coordinator, Australian Shark Attack File, Taronga Conservation Society Australia
MOON PHASES: Perhaps a less serious environmental factor to be vigilant about but nether the less a fascinating one. When a spur of shark attacks occurred in northern NSW there were countless theories as to why such a peak in attacks had occurred. One observation documented by researchers Malia Rouïllon and Nick Brennan, was that the shark attacks and encounters were focused around the two lunar cycles after the first whales have made their migration. They theorise that because due to the El Nino that year, whales migrated up the coast later than what could be considered usual. The slight change in patterns of the whale migration could have caused disruption amongst the great whites sharks feeding opportunities. This could have caused them to move closer to shore, feed on fish and therefore interact with people more. Wildlife activity increases and aggregates on the full moon creating feeding opportunities for predators. Sharks have even been documented leaving shallow water on the full moon and returning on the new moon. Malia suggests that because the whales were late it created less feeding opportunities for the great white sharks at a key time for them, therefore a small amount of hungry sharks had been getting desperate and peaked up to feed on the full moon. This has resulted in more negative shark encounters in the region.
POTENTIAL STEPS TO AVOID AN ATTACK
Avoid wearing contrasting colors and shiny jewellery because sharks see contrasting colors very well and the shimmer given off by jewellery resembles the shine of fish scales. This is particularly true for bull sharks in murky water.
Avoid the color orange- this isn’t necessarily a scientifically backed statement, but one of experience from several people, great whites bite orange.
Remember that compared to everything else in the ocean we are awkward and struggle and sharks will pick up on this and assume we are injured or easy prey.
Avoid anything as simple as peeing in your wetsuit... sharks have been documented being attracted to such bodily fluids and it creates a smell for sharks to follow.
If you are confronted by a great white while free diving in mid water, swim toward the shark as it swims at you... making yourself as large as possible. Sharks will be more likely to investigate if you are rolled up in a small ball, but when you stretch your body out and become a large figure, they are more likely to leave you alone.
Watch the other animals around you... the behaviour of seals and dolphins etc is often your first indication that a hunting great white is in the area.
When sitting in the lineup, it is best to make sure you're with a few people. Sharks are less likely to approach a group, safety in numbers.
Leave the water when you see a species' choice of prey item nearby to avoid mistaken identity: seals, sea lions, turtles, seabirds, tuna, etc. Make sure there's nothing nearby splashing unnecessarily as it will attract the shark to the surface to explore if it's a prey item in distress.
IF YOU ARE BEING ATTACKED
If a shark is circling, it usually indicates pure curiosity, and what happens next will depend on your reaction.
Aim to hit the shark in sensitive areas, the snout, the eyes or the gills.
Panicking and swimming to the shore fast is more likely to get you attacked
Remaining in a group will help deter an attack, sharks like most predators are more likely to
go after an individual.
It is likely that if you see a shark it is just curious, if it wanted to attack it would have already
without being seen.
An inquisitive shark can usually be discouraged by you swimming towards it, and if it is
faced with aggression.
If a shark is coming in try to place anything you have between you and it.
It is important not to panic as there is a chance once the shark has lost curiosity, it will leave
Research has shown that when a kayaker stopped paddling and remained still, great whites
lost interest. But frantic paddling was shown to stimulate the shark’s pursuit behaviour.
If you feel a bump it's best to calmly leave the water.
Coming across a shark in the water does not mean the end, sharks are very inquisitive
creatures, and the key to survival with them is to see them before they attack and use everything in your power to make it see you as another predator in the oceans, and not potential prey.
If the shark persists and gets close enough to do so, punch it in the nose or gills, both sensitive areas on a shark.
FIRST AID The International Paramedic College based in the Ballina, Evans Head and Byron Bay corridor has seen several shark attacks and a number of “incidents” over the last few years. In response they developed a “Shark Attack Pack”. It combines a number of first aid products to deal with traumatic life threatening injuries.
The kit consists of a Combat Application Tourniquet (CAT), two emergency bandages sometimes referred to as an Israeli bandages, a pair of paramedic shears to cut wetsuits and gloves and, training in their use. It’s worth investing in these items and keeping them in your car. Fast responses to these injuries can be the difference between life and death. They also offer first aid courses specific to this type of incident.
Terra Australis also have a small video online showing you the best first aid in a shark attack situation. Please check out the video for more details, here are some of the pointers featured;
Use teamwork and the aid of other surfers to get the victim on top of their board.
Stop blood loss in the water through indirect pressure or using the leg rope as a tourniquet
(wrap it around three times at least).
By staying together with fellow surfers and your boards, you create a large surface area that
helps to deter returning sharks as you swim the victim back to shore.
Apply indirect pressure to the femoral artery, compress the artery to the bone helping to
shut off blood flow and prevent blood loss.
Once on shore, keep the victim on the board, place them on the beach with their head to the
water, elevating their legs up the beach, this keeps the blood flow around the body core.
Use a towel to apply direct pressure, if someone else is available have them check breathing
of the victim.
Once on the beach use a proper tourique to stop the bleeding
Do not perform CPR until the torique is in place
WHY DO SHARKS ATTACK HUMANS
Though over 517 shark species have been identified by science, the three attributed to the most most attacks on humans are: the great white (Carcharodon carcharias), tiger (Galeocerdo cuvier), and bull shark (Carcharhinus leucas).
A document involving changing patterns of shark attacks in Australian waters by John West the curator of the Australian Shark Attack File in Taronga Zoo gives us an insight into attacks. Of the 15 fatalities attributed to white sharks, seven involved a single bite and seven resulted from multiple bites (unknown number of bites for one fatality). Seven fatal attacks by white sharks occurred at the surface while the victim was surfing (33%), swimming (7%) or sail boarding (7%). Eight of the fatalities by white sharks occurred while the victim was submerged, either SCUBA diving (40%) or snorkelling (13%). Of the four fatalities attributed to bull sharks, one involved a single bite and three involved multiple bites. All four fatal incidents occurred at the surface; three while swimming and one while surfing. Two of the four fatalities occurred in human-made canals. Of the three fatalities attributed to tiger sharks, two involved a single bite. One fatal attack occurred at the surface on a sailboarder and two occurred subsurface on a snorkeler and a hookah diver.
Why sharks attack people is a question with multiple answers, and the most common being ‘mistaken identity’. There is a lot of truth to this, we go into the ocean dressed as seals, we are silhouettes of the perfect meal from underneath. Although mistaken identity is a solid theory, I think it’s also important to acknowledge that sometimes we just look like easy food to an opportunistic predator. Yet sharks feel us in the water all the time, if sharks wanted to attack humans or had a taste for us, the beaches would be a no go zone, and the amount of fatalities far higher. So it is safe to say sharks are not after humans, we are not part of their diet. The high metabolic rate of great whites means they prefer high fat content meals, like seals, and the fat receptors in their mouths are the way they determine this. It’s suggested that non-consumptive strikes on sea otters, seabirds, inedible objects, and humans may represent food rejection because of inadequate energy content. This can be seen when studying White Sharks selectively feeding on the blubber but not the underlying muscle layers of a carcass of a whale. What sharks do to humans and most other potential food is merely a ‘test’ bite, which is why most victims end up onshore and the severity of blood loss (another reason for the importance of a first aid kit) will be the determining factor of life or death. In the majority of cases, great white sharks don’t eat people, their aim is not to eat us, but to test us.
Great whites have adapted techniques to the areas they hunt. Great whites hunt seals, and they need to hunt injured seals or unsuspecting seals because seals are too fast and evasive for sharks to go after when they’re healthy. To do this the great white launched from underneath, near the ocean floor, coming up at its prey, and if you look at a surfer from underneath, the silhouette is almost identical to a seal, at least to a great white, it is identical. Realistically compared to tigers and bulls, white sharks show relatively little aggression towards humans, it is merely the power of their teeth and sheer size that makes their movements fatal.
Sharks are designed to hunt weak and injured animals, the way we look in the water, is the way struggling and easy prey looks, and to a shark that is interpreted as an easy meal. There is also a common theory that great whites of a certain size are learning, small great whites are like P-platers, they are learning to go from a diet of fish to mammals, in this time they are changing their hunting habits, learning how to identify and target new prey. This can also be confirmed by the shark attack files stating that over 80% of incidents involved white sharks and tiger sharks less than 3 meters in length. Scientist Alison Towner who conducted extensive research into the hunting habits of great whites saw significant difference in the experienced and not so experienced great whites...
“My volunteers and I were tracking a large male in Shark Alley, an animal we know has been returning to the island for more than 12 years. For the first eight hours he patrolled back and forth, seemingly uninterested in prey. Then, to our surprise, he rushed directly up to the rocks and grabbed a seal as it was half out of the water on the rocks and devoured it. Another younger white shark we tracked west of the island tried predation on a seal, missed it and proceeded to chase its own tail.”
Other culprits include tiger sharks, which are essentially large scavengers and will opportunistically attack something they believe poses no threat to them. As well as bull sharks, which were mentioned earlier. It would be smart to learn which of these are in your local area, and then study up on that particular sharks. Each species has specific traits and diets and time that influence the chances of an attack. Knowing what you are up against is the obvious way to share its their home.
Another theory I read about in the Shark Attack Theories documented by John West the curator of the Australian Shark Attack File in Taronga Zoo, is that sharks are aggressive to humans, as they are to other sharks. Many species of sharks display social and aggressive behaviours towards each other. These behaviours, which are common in species that congregate in large schools, are usually associated with size and hierarchies of dominance. It has been observed that smaller white sharks give way to larger white sharks especially when feeding. The types of wounds seen on some sharks are similar to those inflicted on humans from a single raking type bite.
I have spent a small amount of time in the water with white sharks, but enough to develop a respect and understand that they differ from other species of sharks. Whites are smart, they are very smart, they are incredibly inquisitive and this trait, in a large marine predator that hunts mammals, is dangerous. There is no mystery solution for shark attacks, the reality is we can try make our interactions safer but these sharks can be dangerous, and unless we stay out of the water forever,
there is no 100% way to deter an animal that is this smart, and this capable of curiosity. I watched them change their methods to take bait, sneak up on us, disappear and come back with a new plan. I watched great whites problem solve, and although the minimum but decent time I have spent outside a cage in the water with them has shown me they are testing but also very cautious and curious.
WHY SHARK NETS AND SHARK CULLS ARE NOT THE ANSWER
If the presence of a solution to attacks on humans was as simple as shark nets or culls it would not be so widely opposed, however the reason most people who work with and study sharks oppose these methods is not because they are against the death of sharks, but also they know that these methods are not effective. Often they paint the issue as solved leaving a false sense of security amongst the community that can in turn lead to more shark related deaths.
NETS More than 30 shark attacks have occurred at beaches with shark nets on the Gold Coast, the reason you never hear about them is because they have not become fatalities... that’s because beaches with shark nets are all patrolled, a shark attack has an immediate response from lifeguards and a far quicker response time from paramedics, meaning no death from blood loss. The sole purpose of the nets is to give tourists and locals a false sense of security, the government section devoted to maintenance of the nets states a revealing summary of their purpose “The shark control program (SCP) relies on nets or drum lines, or a combination of both, to minimise the threat of shark attack on humans in particular locations. It is not designed to provide a distinct barrier between sharks and humans and to remove high risk sharks from a particular location.”
The nets do not stop attacks, the nets have even taken a human life, killing a young boy after becoming loose and entangling him. The program in Queensland has captured approximately 78,000 marine animals since the sixties. Most of the animals caught in the nets are caught heading from the beach side back out to sea, there is also a long list of animals such as dolphins and turtles that have been caught in these nets, then found half eaten by something much bigger that was never caught in the net... nets act as a form of chumming, a buffet of dead animals, attracting sharks in to feed from them.
CULLS We witnessed an attempt by the Western Australian government to implement a shark cull after a series of attacks on surfers in a short time period. The shark cull caught over 100 sharks, mostly tiger sharks, not a single great white. Tiger sharks have not been responsible for an attack on humans in that area for over 80 years. The species implicated with attacks on humans are mostly great whites, great whites cross oceans, they migrate, and eliminating their local population would not prevent a new one coming in. The other thing we seem to forget is that baited drum lines are food to sharks, as the tide runs out and carries the smell of rotting food potentially chumming the area.
A shark cull could never cull the entire population of great whites sharks and therefore make the ocean safe. The consequence of removing a slow growing apex predator whose place in the food chain already means there are few of them also has environmental ramifications. I think it would also be important to point out that protection measure against sharks are a wonderful idea and I am not against it, but the cull is not one of those measures. I am often asked if I am against shark culls most people associate my answer with a lack of respect for human life. I assume the purpose of the cull is to protect human life, and I am not against it because it kills sharks, but because as a method to protect human lives, it fails.
SHARKS AND BLOOD
It’s true, sharks can detect one drop of blood in a million drops of water, but do they react to it? The truth is sharks are attracted to the blood of fish and other marine animals, and human blood is not on their radar. I’ve suffered cuts and nose bleed in the middle of a shark feed with no reaction from the sharks. HOWEVER, sharks can pick up electricity, like the faint electricity created by the bioelectrical impulse of a heartbeat (more on this in the next section). The skin acts as an insulating layer, and blocks a lot of that signal. When you are cut, that insulation is compromised, allowing your electricity to go through the water easier and therefore stronger. If you are injured in the water and have a
cut, your heartbeat will be stronger. To a shark, that means injured or scared, and sharks only eat injured and scared. This does however only take effect in the last few meters of contact, however be aware that human blood doesn’t turn sharks into Jaws.
In addition, blood, urine, body odour and electromagnetic fields will quickly dilute or dissipate in the ocean. One drop of odour concentration in moderately turbulent flowing water would dilute at one kilometer away, which would not be recognised as blood or even register as a stimulus. There would need to be large amounts of blood flowing from the source for this to occur. As an example, one need only consider the amount of ‘chum’ or ‘burley’ needed to attract a shark to a fishing boat. Some sharks have been known to swim past several people in the water to
focus their attention on an individual within a group of swimmers or surfers. It is more likely that the shark’s selection process may be more related to the behaviour or activity of an individual rather than the scent of an individual’s blood or other excretions.
SHARKS AND YOU
Shark scientists say a shark can hear you from 1,000 to 10,000 meters away; smell, see and sense you at from 10 to 100 meters; and perceive you electromagnetically via sensors called ampule of lorenzini at half a meter (50 cm), before switching to direct contact. We see examples of this when metal is in salt water it emits a very strong electromagnetic field which can over stimulate the shark’s sensory perception and they bite things like a metal boat propeller or shark cage. It is more likely that a shark is attracted by a person’s activity in the water rather than the relatively low level of electromagnetic field a human may produce.
It has been well documented that sharks are attracted to low-level frequency sounds particularly in the range or 10 Hz - 50 Hz which is within a frequency also given off by struggling or injured fish. Tests have determined that sharks use their lateral line and inner ears to locate prey as far away as 250m or more. Human activities in the water may attract a shark’s attention. Sound, rather than sight or smell, seems to be a shark's primary cue for moving into an area from any distance. However, once they are attracted to the source of the sound they are more likely to investigate the object relying more on sight than hearing.
Their vision varies between species but research has suggested they can see colors but mainly contrasts, which is why so much shark deterrent work has been done around the visual capabilities of sharks. Great whites are suggested to be more attracted to yellow than any other color for unknown reasons. However the strongest sense of a shark remains, its smell. This is why its important to notice if fishing is occurring in the area, or if a dead whale is washed up, it means there is a smell line going out to the ocean which may bring sharks into shore.
HAVE SHARK POPUATIONS BOOMED?
There has been speculation that overfishing is depleting the world’s fish stocks and sharks are starving and seek out humans as a source of food. While it may be true that commercial fishing has depleted fish stocks in some areas of the ocean most large predatory shark species (particularly those species known to bite humans) have the ability to travel long distances to other feeding grounds and do so as part of their normal distribution and migration behaviour. Changes in prey item preference and the diversity of food items found in shark’s stomachs would also give these sharks a broad range of food items to pick from. A ‘starving’ shark is more likely to move to where their preferred food is more available, not less.
Another of the myths is that shark populations have exploded. Within the animal kingdom, sharks are famously slow reproducers. Female great white sharks, for instance, typically produce a couple of offspring every other year, and only start reproducing once they reach 17 years of age. As a result, sharks are biologically incapable of “baby booms” and indeed are very sensitive to even low levels of fishing. We may be seeing more sharks in some specific areas due to changes in ocean conditions, but not more sharks, and not a boom in populations. Of the over 500 species of sharks, only a handful of species have been linked to any incidents with humans – that is less than 5% of all shark species.
One indicator of shark abundance is the beach protection program in NSW where catches have been monitored for decades and provide a long-term data series. From the introduction of the shark- meshing program in Sydney in 1937, 1500 sharks were caught in the first 17 months, an average of 88 sharks per month. Within a decade, catches from the SMP averaged less than eight sharks per month in the Sydney region. Almost all species have declined over that period. Declines in the number of sharks captured following the introduction of shark-control measures were also found in Queensland. The shark meshing and commercial catch-rate declines suggest that the increase in reported shark attacks over the past two decades is not a result of increasing shark numbers.
SHARK MITIGATION DEVICES
EYES Shark are ambush predators, as we’ve discussed, so one technique I once head about surfers using was eyes in the bottom of their surfboards. I have seen the effects of eye contact with shark a number of times especially tiger sharks, it deters them from an ambush patter they rely on to get close to prey. Painting eyes on your board can create a potential deterrent to sharks due to the constant eye contact, when prey is aware of their presence, it makes an attack harder for the shark.
STRIPES The banded sea snake is a highly venomous creature and is defines so by its distinctive stripes, although these don’t help with camouflage, they do help the animal with defense against predators. Sea crates (?) and other brightly colored or striped animals have that distinctive pattenr because that is nature’s way of signifying to predators that they are venomous and dangerous to eat. So the idea with having stripes on their board, is to signify you are venomous. Both designs can be done with a simple stencil or free hand with some spray paint. However this isn’t the only reason why stripes are being considered a deterrent these days. The new theory with more scientific relevance is that the stripes break up your contrast in the water, and instead of a seal shaped sillouette you are now a broken up pattern and not one large object, a very handy thing to have around ambush predators. This theory can be seen by a company called SAMS who are developing wetsuits and boards that use this method. It was first documented by scientist Eugine Clark, who discovered captive lemon sharks were able to associate pushing a yellow button with receiving food, however when the button was painted with black and white stripes, they simply couldn’t find it.
SHARK SHEILDS Although the shark shield was recently found effective in deterring large sharks, it relies on factors like when or if it’s on, how the shark approaches etc. It is however the world's only scientifically proven and independently tested electrical shark deterrent, and has been in development for more than 20 years. It is important not to surf under an illusion of full protection, but shark deterrents like this one, although expensive, are undoubtedly useful.
“From my reading of the various scientific testing that has been done on shark shields and other similar deterrent devices, their effectiveness is really context specific and depends on the motivational state of the sharks. For example, a shark shield may be effective for a curious Great White that approaches a surfer with curiosity, but not for a Great White that is charging from below in full attack mode."
- Dr Peter I. Macreadie
Senior Lecturer, Australian Research Council DECRA Fellow & Plant Functional Biology and Climate Change Cluster, UTS Centre for Integrative Ecology
School of Life and Environmental Sciences, Faculty of Science Engineering and Built Environment, Burwood, Deakin University
The reality of the environment here in Australia, and anywhere around the world, is a reality we have forgotten, it’s not ours, and it’s dangerous, and it means we may have to abandon a perfect break every now and then to avoid becoming a victim to a shark attack. It is also important to remember that reacting to shark attacks in the name of the public is a good political move, it is not always done with the intention of putting on the correct time or effort to help people but rather the best looking action. The very real threat of sharks needs to be taken into our own hands sometimes, and not just that of the governments. Sharks are not a mystery, they are not an enigma, there are many things you can and should learn about the dangerous predator you enter the water with, as hikers do with bears, and many other examples. So my advice to you is this, know your place in the ocean, and accept that risk and your own personal attempts to make it safer for yourself, but never forget that its is not our ocean. And although they can be called the enemy of every surfer, spear fishermen and unsuspecting snorkeler at times, and it seems to protect an animal that is bred in nature to destroy us if we find ourselves in the wrong situation with them, it is our responsibility. If we want to exist in the oceans, surf in them and take from them, then the issues sharks face are not for people like myself who’s life revolves around them, but everyone one of us who’s life revolves around the ocean they control as apex predators. We need to make co existence part of today’s culture, being in the presence of greatness like the sharks, although sometimes terrifying, is not only an inevitability... it is a privilege.
"The thought that we can engineer nature to make it safer for humans sends a chill to my heart. People need to take responsibility for their actions, which includes being aware of and accepting the risks of entering the ocean.
I believe that the best way for us to protect sharks is to better understand galeophobia (fear of sharks) and, most importantly, change our cultural views of sharks. Our biggest investments should be in rewiring society's views of sharks."
Assistant Professor, Watershed Sciences and Ecology Center, Utah State University
It is important to keep the risk of a shark attack in perspective. On average, 87 people drown at Australian beaches each year (SLSA 2010), yet there have been, on average, only 1.1 fatalities per year from shark attack over the past two decades. It is clear that the risk of being bitten or dying from an unprovoked shark attack in Australia remains extremely low.
Changing patterns of shark attacks in Australian waters
John G. West
Coordinator, Australian Shark Attack File, Taronga Conservation Society Australia
Major thank you to all those who’s scientific findings were featured and for anyone who took the time to read and take responsibility of entering the oceans into their own hands.
Please feel free to contact me with comments or concerns at www.thehoopercollective.org