by Peter Pinnock
It should not take too long,â says Mark Addison confidently as he tosses a sack of sardines over the side of the boat. We are anchored five kilometres off the small holiday town of Scottborough on South Africaâs east coast. Mark Addison is owner of Blue Wilderness â a company that specialises in marine adventures. I am here to photograph the elusive tiger shark.
âYesterday we got our first tiger within 30 minutes!â I am pleased to hear that. On previous tiger shark dives it took hours for a tiger shark to appear. At other times we had no luck at all. The tiger shark is a reclusive animal. It is unlikely that you will see it during the course of a normal dive. Hence baiting is essential. The bag of sardines soon leaves a greasy slick on the surface that drifts south over the off-shore reefs of Scottborough. The slick is irresistible to any tiger shark that passes through it. To add to the temptation a large yellow fin tuna is suspended behind the boat.
âPerfect conditions for tigers,â Mark assures us confidently. There is always a current off Scottborough and it plays an important role in attracting the sharks. The current has to be just right. If it flows to the north or out to sea, the chances of attracting a tiger shark to the boat are drastically reduced. True to his word, a tiger shark soon appears. The ominous brown shadow is easily identifiable beneath the surface as it slowly approaches the boat. We start to kit up.
The coast of Kwazulu-Natal is well known for its diverse shark population. The best known species is the ragged-tooth shark that migrates up the coast during the winter months of July-October. Divers from around the world flock to Aliwal Shoal for the opportunity of diving with these docile creatures. Hammerheads, mako, copper and whale sharks are also found along with the three most potentially dangerous sharks known to man: the great white, bull and tiger shark.
The tiger shark is without doubt one of the most dangerous species of sharks. Its highly diverse diet and large maximum size (7.2 metres) makes it one of the most threatening sharks to humans. You have more chance of surviving an attack by a great white than by a tiger shark. Great white attacks on humans are normally considered to be prey misidentification â the white shark takes a bite to investigate its prey whereas a tiger shark will saw to pieces and devour almost anything it can eat. With this in mind and knowing there were tiger sharks around the boat, I descended cautiously to the reef below. Cages are not used when diving with tiger sharks. The rough sea conditions off Kwazulu-Natal make the use of unwieldy cages impossible. Instead we huddle together in a cave. The cave is not for protection. It is to hide us from the shy tiger shark. We also hope that the interior of the cave will diffuse our bubbles as tiger sharks are scared of bubbles. Thatâs right â tiger sharks avoid divers and are scared of bubbles. Mark places an assortment of tuna, steembras and sardines in front of us and the waiting begins.
The tiger shark is easy to identify. The blunt snout and distinct dark grey vertical row of spots on the upper body render the shark unmistakable. Markings are darkest at birth and fade with age, such that they may be absent in adults. Despite its voracious habits, the tiger shark is a sluggish species and is capable of pumping water over its gills for respiration. This enables it to swim at slower speeds than most sharks who need to keep up a faster pace to maintain an adequate flow of water over their gills.
A shadow moves above our heads. I immediately think it is the boat on the surface. Instead it is a large female tiger shark. The size of these animals never fails to surprise me. This specimen is over three metres long and already the stripes on the side of her body are beginning to fade. A shark this size will weigh in at over 400kg! Accompanying her are a pair of remoras, ready for a free meal. Slowly and apprehensively the shark circles the bait. It then moves out of our line of sight and reappears a few minutes later. Tiger sharks are very cautious and often they will make repeated approaches to the bait before finally attempting to feed. This individual is no exception.
Eventually she makes a direct approach to the bait. Gliding gradually into the current she reminds me of an aircraft gently coming in to land. Like a discerning diner, a piece of fish is ed and devoured. I shake my head in disbelief. It is difficult to believe that a graceful creature like this could be portrayed by the media as a cold blooded man-eater. Nevertheless, shark attacks on humans do happen. During the âBlack Christmasâ of 1957 five lives were lost due to shark attacks on the Durban South Coast. Tourists hysterically flooded away from the coastal resorts leaving virtual ghost towns. For a year the tourist industry was crippled. The dramatic effect that shark attacks have on tourism made it essential to keep sharks away from popular swimming beaches and in 1964 the Natal Sharks Board was given the responsibility of providing this protection. Shark nets were erected off all major beaches and today there is approximately 29 km of nets at 36 sites along the Kwazulu-Natal coastline. Similar nets are used in New South Wales and Queensland in Australia as well as Dunedin in New Zealand. Shark nets are positioned in two rows with gaps between the nets. The nets are anchored in water 12 metres deep and buoyed so they hang suspended about three metres from the surface and a similar distance from the sea floor. Thus the sharks can â and do â swim over, under or around the nets. The nets do not offer direct protection to the swimmer. Their effectiveness lies in the entangling of the sharks and thus reducing the numbers of large sharks to the point that attack is unlikely. The nets have been highly successful in reducing the number of shark attacks on bathing beaches in Kwazulu-Natal, but not without controversy. In addition to 1200 sharks netted annually, large numbers of non-target species including dolphins and turtles are also caught. Unfortunately economics dictates that the nets will never be removed.
Between 1978 and 2001, a total of 1133 tiger sharks were caught in shark nets. The Natal Sharks Board reports an average of 47 tiger sharks killed every year. Thatâs a lot of tiger sharks. Sharks that are still alive in the nets are returned to the sea and dead sharks are brought to the Natal Sharks Board for dissection. Studying these tiger sharks has revealed an interesting insight into the animal. Of particular interest is the stomach content which displays their diverse eating habits. Manta rays, devil rays, dusky sharks and ragged-tooth sharks are the most important prey group. Reef fish are the second target group including catfish, triggerfish, kingfish, porcupine fish, spadefish, grunters, rockcod and mackerel. Mammals form the third most important group and include bottlenose dolphin and common dolphin. The tiger shark also feeds on birds resting on the surface of the ocean. The most common bird is the Cape gannet. The tiger shark is the only shark that preys on sea-turtles. Their teeth are uniquely shaped with oblique cusps and coarse serrations. The tiger shark has evolved a feeding behaviour that involves a rolling motion of both jaws which cuts in a saw-like manner. This motion, combined with the specially shaped teeth allows the tiger shark to cut cleanly through bone without damaging the teeth. Other stomach contents revealed cuttlefish, crabs, plastic bags and land mammals â washed out to sea during floods. The tiger shark is an eating machine. It appears that there is nothing it will not snack on!
Tiger sharks feed individually. It also appears that they have their own social hierarchy. Two smaller tiger sharks are attracted to the bait but retreat when the larger female is present. There are many lessons that we learnt from observing tiger sharks. One is that even though the tiger shark is a formidable predator, it knows where it stands in the food-chain. During one particular dive there were three tiger sharks in the vicinity of the baiting station. As if given a secret cue the tiger sharks disappeared, only to be replaced by a great white. There can be little doubt who heads up the food-chain.
âThat sharkâs name is Marion.â Mark has individual names for each shark. They all have characteristic markings or behaviour patterns. Marion is easily identifiable by a large gash behind one of her eyes. The tiger sharks of Kwazulu-Natal are not migratory. Sightings of the same animals are reported year after year. Unfortunately not all animals return. During the writing of this story three tiger sharks were caught in a shark net at the same time. It is easy to visualise how a shark thrashing to fight its way out of a net can attract other sharks to the area. Mark is visibly upset when the news reaches him. It is almost as if one of his favourite pets has died.
There are oceans on this planet that have been completely depleted of sharks because of manâs insatiable appetite. Shark-fin soup made from shark fins fetches a handsome price. Sharks are not killers but, they do kill. Sharks just do what they do best â follow their primitive instincts. Referring to a tiger shark as a killer implies a ruthless, cold-blooded animal. After observing a tiger shark in its natural habitat, it is obvious that none of these apply. This is no villain – tiger sharks kill to survive. So do humans. The odds of being attacked by a tiger shark are minimal. There is more chance of an airplane falling from the sky and killing you. We are privileged to be able to dive freely with these imposing sharks off the east coast of Africa. It is a memorable and adrenalin charged experience. Perhaps the first impressions painted by the media of this majestic animal are wrong? I suspect that the tiger shark could be in critical need of some good press.
Season: Tiger sharks are present all year round. The best time to view them is from January to May..
Mark Addison has an unsurpassed knowledge of the local fish fauna and sea conditions.