Chondrichthyes (cartilaginous fish, including sharks, rays and chaemeras) >

Shark attack

There are few phenomena injurious to people that are more misunderstood than shark attack. Popular perceptions and statistical realities are separated by a vast gap of fear, supposition, and ingrained images or archetypes. Sharks have been long been known to attack people, but at an extremely low rate compared to the vast number of people at risk. 

Shark attack in Southern Africa

The pattern of shark attack off southern Africa is similar to other regions in being positively correlated with sea temperature. This is related to the greater number of people using the sea for recreation in warm-temperate and subtropical waters of the east coast and also to the greater diversity and abundance of potentially dangerous sharks in warmer waters.

Attacks on swimmers, surfers and divers occur at a low rate along the west and east coast from Namibia to Eastern Cape. Very few attacks have been recorded from Namibia to Cape Town, although Great white sharks and Spotted sevengill sharks are common on the west coast and have been encountered by divers underwater. Shark attacks are commoner on the southwest and southeast Cape coasts, with most occurring in False Bay and off East London. 

KwaZulu-Natal's warm climate and warm temperate sea has long made it a holiday Mecca, particularly for inlanders who flock to the sea for their vacations. This coast has a higher rate of shark attack compared to the Western and Eastern Cape coast although absolute numbers are small.

Widespread shark netting off the Natal beaches started in earnest in the mid-sixties and has had a marked effect in reducing shark attack from netted areas. The nets do not, however, act as an absolute barrier like a shark enclosure, and a few attacks have occurred inside the nets on netted beaches. With improved knowledge concerning treatment of attack victims, especially by lifesavers of the Surf Lifesaving Association of South Africa (SLASA), fatalities of attack victims have been reduced.

Increases in shark attack from the 1940's to the present have been slight, even in areas where shark nets and other forms of fishing have not reduced the resident shark population. This is despite increasing use of the sea by a rapidly expanding population. Furthermore, there has been a postwar increase in water sports as a result of advances in technology that produced aqualungs, wetsuits, fibreglass surfboards and fishing equipment which has resulted in a concomitant introduction or popularization of sports such as surfing, SCUBA diving and spearfishing. These sports take people well beyond the inshore protection of shark nets and into unnetted sections of coastline, but there has not been an onslaught of shark attacks proportional to the increasing numbers of people utilizing the water.

The higher attack rate in KwaZulu-Natal compared to Cape waters has been attributed primarily to greater numbers of people in the water, particularly off popular tourist beaches. An additional contributing factor is likely the greater diversity and abundance of potentially dangerous sharks in warmer waters, particularly a few species of large, powerful and omnivorous requiem sharks such as the Zambezi and Tiger sharks. The fatality rate for the decades 1940-49, 1950-59, and even 1960-69 (during which period shark netting off beaches began to reduce the numbers of potentially dangerous sharks) is strikingly higher than in Cape waters. This may also reflect a difference in the species composition of sharks perpetrating the attacks: Great white sharks, the principal attackers in Cape waters, show a strong inclination to abort attacks on people, while off KwaZulu-Natal some of the attackers (presumably omnivorous requiem sharks such as Tiger and Zambezi sharks), may tend to actually feed on people. The reduction of shark attacks from the late sixties to the present time, after the shark netting programme was well underway, is correlated with the decline in numbers of resident omnivorous sharks, particularly Zambezi sharks, as evidenced by shark net catches.

Anti-Shark Measures

In former times bathing enclosures were used in Natal to protect swimmers from sharks, which were effective but expensive to keep repaired. Following the lead of Australia, where gillnets were installed off the Sydney beaches in New South Wales in the late 1930's, the Durban municipality opted for the more aggressive and flexible method of shark netting off bathing beaches, which reduces shark attacks by killing large, potentially dangerous sharks. Present anti-shark measures in Natal rely on gillnets installed by the Natal Sharks Board (NSB; once called the Natal Anti-Shark Measures Board), which came into being as a direct result of the media-fanned fear of shark attack in the vacationing public during the late 1950's. More importantly, anti-shark measures, and the NSB, grew from the economic fears of business interests in Natal which had suffered from the results of a spate of shark attacks in Natal during the Christmas holiday of 1957 and 1958. The public deserted the beaches en masse after `Black December' and caused a marked decline in the local, recreation-based economy.

In 1983 some 45 beaches were netted by the NSB in Natal, with 381 nets deployed, each net being 100 m long (except for 300 m nets deployed around Durban). Present numbers of nets are probably over 400, with over 46 beaches netted off Natal and northernmost Transkei. The numbers of nets deployed per beach are dependent on local conditions. Large resorts and municipalities pay for the cost of the nets, but smaller entities have part of the cost defrayed by the Natal authorities.

The NSB has a large, impressive headquarters at Umhlanga Rocks which is its administrative and logistics centre, with sections for net building and repair, staff housing, boat and vehicle maintenance, research, and public relations. Considerable scientific data is collected by the NSB on netted sharks, from netting teams and from dissection by NSB scientific personnel at Umhlanga Rocks. Such data is entered into a computer database which is currently being extracted for publication by NSB scientists, and will eventually become available on the biology of several species of sharks caught by the NSB nets.

Sharks taken by the NSB ranged in number from 808 to 1,842 per year from 1968 to 1983 (average about 1,151 per year), for a total of 18,423 sharks taken. This does not include sharks taken by the Durban municipality from 1968 to 1979, which during this period operated independently of the NSB. For the period 1978 to 1984 the Natal anti-shark nets yielded about 8,333 sharks, of which approximately 9.7% were Great whites, Zambezi, and Tiger sharks, considered the most dangerous local species by various authorities. Another 2.8% were Great hammerheads and Java sharks, potential attackers, and 1.2% were Shortfin makos. Most sharks taken were of minimal danger to humans: Spotted ragged-tooth shark, 12.0%, Dusky sharks, 18.6%, Copper sharks, 12.6%, Sandbar sharks, 2.0%, Blacktip and Spinner sharks, 20.6%, Scalloped and Smooth hammerheads, 18.9%, others 1.6%. Other animals caught in the nets, including rays, turtles, and dolphins, are released by the netting teams if still alive, and lately live sharks are being released also.

The NSB has changed qualitatively in greatly increasing its public outreach programs, displays, and other public relations work that promulgates a positive image of its activities, and encourages their continuation and expansion. This interlinks with public ignorance of the minor danger of shark attack and its unreasoning fear of sharks, the tendency of the newsmedia to overpublicize shark attacks and frighten the public, and the expanding tourist industry. With a circular logic in a positive-feedback loop, the presence of shark-netted beaches generates the demand for more shark-netted beaches as new resorts open or smaller ones with netless beaches become larger or more popular. The same thing happened in Australia: the netting programme off the state of New South Wales spawned a new netting operation off Queensland as that state's Gold Coast developed for tourism, despite the low frequency of shark attacks there.

No efforts have been made to extend the activities of the NSB elsewhere in southern Africa except northern Eastern Cape, and the defined sphere of operation of the NSB is limited by its charter to KwaZulu-Natal. There have been sporadic and abortive attempts to install shark nets off East London and in False Bay in the past few decades following a few overpublicized shark attacks and spates of shark hysteria and paranoia.

The increasingly wide-ranging activities of the NSB has generated considerable controversy in KwaZulu-Natal. There is concern on the ecological effects of long-term shark netting, particularly amongst anglers, scientists, and conservationists. Obviously, the specialist anglers who fished for big sharks in southern KwaZulu-Natal have been adversely affected by the shark nets, and have either abandoned their sport or go further afield to northern KwaZulu-Natal or northern Eastern Cape for large sharks.

Anglers and scientists have noticed a marked increase in numbers of juvenile Dusky sharks, Milk sharks, and possibly other small sharks in the past decade, and attribute this to the shark nets. According to this view, which is opposed by the NSB, the shark nets have depressed the numbers of larger sharks that feed on smaller sharks, and increased the survivorship of young dusky sharks and in small sharks generally. There is an apparent decline in bony fishes targeted for sport, which may be induced by greater numbers of juvenile and adult dusky sharks as well as increased angling pressure. In the ensuing controversy, the NSB denied that such an increase in dusky sharks was occurring, but organized anglers, commercial fishermen, and fisheries scientists in KwaZulu-Natal have argued otherwise from long-term fishing records.

A heated and emotional public controversy arose over dolphins caught in the shark nets. The long-term effects of shark netting on inshore dolphin populations are uncertain, but some segments of the Natal public have reacted strongly to the killing of dolphins by the nets. From the late 1960's onwards, dolphins and other cetaceans have acquired an intensely positive, anthropomorphic public image in the West that generates strong sympathy for them (`Flipperphilia') and action against people who cause their demise (`save the whale' campaigns). While the small sharks and dolphin controversies still rage, there is currently no move to independently access the ecological effects of shark netting in the much broader and massive context of human-induced environmental degradation along the Natal coast.

Alternatives to current Anti-shark Measures

Shark netting originated at a time when knowledge of the biology of large sharks was minimal, and when it was blindly assumed that all large sharks were dangerous and potential `maneaters'. At present we know that even the most powerfully armed sharks will not automatically attack people in the water. To put it bluntly, human beings are not `on the menu' of large predatory sharks, which normally eat aquatic organisms. This is different from some of the large terrestrial carnivores, such as lions, tigers, Spotted hyaenas, leopards, the larger bears, wolves, and the largest crocodiles, which in primitive times probably included humans as regular prey. Large sharks may approach divers without any attempts at predation and may depart without aggression, but may also give warning displays and inhibited threat bites similar to those used on members of their own species, on other sharks or on other marine organisms. Numerous encounters between divers and Great white sharks suggest that this formidable superpredator may not normally regard human beings as prey. This seems true for large species such as the Spotted ragged-tooth which differ from the white shark in largely feeding on fishes and invertebrates and avoiding mammalian prey. The most dangerous sharks may be the few species of omnivorous requiem sharks (family Carcharhinidae), particularly the Tiger and Zambezi sharks, which are highly opportunistic feeders like the Spotted hyaena and readily take mammalian meat, carrion and garbage. However, even these sharks will not automatically attack divers underwater, and probably only rarely turn their attention to swimmers and bathers as actual prey. Shark netting seen in this context is unselective and analogous to dealing with the problem of occasional man-eating lions or tigers in a game park by randomly shooting all carnivores down to the size of caracals and jackals, and potting some of the ungulates for good measure!

Several alternatives to shark netting are possible. The NSB has as its primary mandate the protection of the beaches of KwaZulu-Natal, which does not necessarily lock it to shark netting and could include its major participation in the development, promotion, and maintenance of non-lethal alternatives. We suspect that shark netting became popular in Australia and in KwaZulu-Natal not only because it reduces shark attacks, but because it actively and aggressively destroys the `enemy'. Such a macho, warlike public reaction to large apex predators has been common in the past, but has been largely superseded by a tolerant, unaggressive, respectful approach toward dangerous terrestrial predators. This has partly extended to sharks by the experiences conveyed by divers and diving scientists to the general public, which show sharks as far more benign creatures than the ferocious, malevolent JAWS bogeyman promoted by the popular media. In the light of the continuing controversies over shark netting, and public concern for its possible environmental effects, we mention a few alternatives here.

Dr. E. D. Smith of the National Physics Research Laboratory developed a pulsed-current cable system that forms an electromagnetic barrier to repel sharks. After initially promising results with a small shark cable in a tank at the Oceanographic Research Institute, Durban, full-sized cables were installed in the sea off a beach at Margate, but ran into chronic and expensive operational difficulties. Problems with electronic equipment gave inconclusive results in a 1988 series of field tests of the latest version of the cable at Margate, and the future of government funding for the programme is in doubt. The electronic cable remains one alternative to netting despite the operational problems at Margate, but needs much additional testing and expensive modifications that may not be pending. There have been individual electronic shark repellent wands marketed in the USA that can be carried by individual divers and which will ward off inquisitive sharks.

Shark enclosures could be built using modern, lightweight, strong materials such as new alloys, plastic composites, and new high-tensile strength fibers such as Kevlar. These may be able to withstand the destructive and corrosive action of the sea more effectively than the steel enclosures used in earlier times. If used in conjunction with existing pier structures, or with specialized multiple-use recreation piers, these could even be removed in the event of extremely heavy seas or floods. The city of Durban recently built an elaborate and expensive set of public wading pools along the beachfront to cater for tourists, and such assuredly sharkproof facilities can be extended to the ocean itself. Intact enclosures have the advantage over shark nets of offering 100% security from shark attack without removing sharks or other marine life. Materials and site research and development is necessary to produce modern shark enclosures and shark-proof breakwaters that can fit into plans for city beach development. Equivalent protection for divers includes small portable shark cages developed in Australia for commercial perlemon (abalone) divers, and steel-mesh shark armour that fits over ordinary wetsuits.
The use of ultralight spotter planes, small piston-engine helicopters, or small blimps by lifesaver-observers may also prove a non-destructive method of preventing shark attack by warning bathers when large, potentially dangerous sharks approach them. Our own experience with helicopters and light planes show the effectiveness of aerial observation in spotting sharks off beaches. The advantage of using microlight aircraft would be the greatly reduced operating costs compared to conventional light planes and helicopters.

Technological innovations may yield a method of detecting sharks that approach too close to bathing areas on beaches using automated remote sensing techniques that can issue warnings to bathers and swimmers. Such equipment is readily available for land use, and it is probably a matter of time before an equivalent can be developed for bathing areas.

Research on shark repellents in Israel and the USA have finally yielded effective substances that can be used to protect divers and bathers from shark attack. Certain industrial detergents (including sodium lauryl sulfate) have a powerful effect in repelling sharks, and have been successfully tested in the field by scientist-divers. Possible uses include shark-billy applicators for divers that squirt a jet of repellent at an approaching shark, shark-repellent salves, special repellent wetsuits for divers, surfers and bathers, and even shark-repellent coatings for surfboards. The Moses sole, a small flatfish of the Red Sea, secretes a natural shark repellent that inhibits sharks from biting it, which could be imitated by shark repellent apparatus designed for human use.

In view of the heavy mortalities to sharks caused by fishing activities along the coast and the low number of attacks, it has been suggested that the expense and effort of a provincial shark netting programme may, in fact, be unwarranted. As shark products increase in value worldwide and recreational angling for sharks becomes more popular in southern Africa, increased commercial and recreational fishing with line gear may be able to substitute for netting programs and will accomplish the same purpose, depletion of stocks of potentially dangerous sharks. Although dolphins, turtles and some rays would not be affected by line gear, the environmental impact of removing large sharks would be the same no matter what gear is used, and such fisheries would have to be carefully regulated to insure the survival of local sharks.

An alternative approach to shark attack, which is apparently repugnant to many but not everyone in KwaZulu-Natal, is non-intervention, as currently practiced on the Cape coast as well as in California, Hawaii, Florida, New Zealand, and several other places where shark attacks are regularly reported. Florida has a larger and more valuable tourist industry than KwaZulu-Natal and a higher rate of shark attack (14 in 1981) than Natal prior to shark-netting, but has no anti-shark measures whatsoever. California has its shark scares and media hyperbole as in southern Africa but nothing is done except to occasionally close beaches and post warning signs on beaches off which shark attacks have occurred. Up to 7 attacks per year have occurred there, but this is miniscule compared to the vast numbers of people using the water. There are upwards of 400,000 registered SCUBA divers at any one time in California, plus numerous commercial abalone and sea urchin divers, skin divers, surfers, swimmers, commercial fishermen, and anglers that share the water with large white sharks and probably vastly outnumber them, yet attacks are few and far between.

Finally there is a obvious need for the public to be educated on the realities of shark behaviour and the minor objective importance of shark attack. Shark attack should be demystified by the same kind of educational processes used in dealing with other dangers of sea and shore. Hopefully this book will contribute to this process, and to public education. We see the popular newsmedia, which have so often helped to instill shark paranoia and hysteria in the past, as instrumental in promoting a sober, realistic awareness of the nature of sharks and of shark attack. Serious threats to human life such as automobile accidents are routinely reported in a straightforward fashion, without the gory and unnecessary embellishment of shark attacks. We hope that news reporters and editors will assimilate the realities of sharks and shark attack, and will voluntarily refrain from emotional, sensationalist, self-serving reportage in the future. Overheated shark-attack accounts help to perpetuate the myths of shark attack and the killing of sharks at a level far, far higher than the few human fatalities.

Shark Sense

The low incidence of shark attack can be further minimized by taking due care while using the sea (`shark sense'). Each of us have had personal encounters with sharks and the following advice is given from these experiences, from the advice of colleagues, and from general advice in various publications.

To lessen the likelihood of attacks, swimmers should not: 1. Bathe at night in the sea. 2. Swim in turbid waters, especially when rivers are disgorging large volumes of sediment into the sea nearby. 3. Swim when bleeding either from a laceration or during menstruation. 4. Swim alone far from shore over deep water. 5. Swim in the vicinity of popular fishing spots, particularly in deep water.

Divers should not: 1. Have speared fishes on their belts, because they may be injured by sharks trying to eat the fish. 2. Dive where known concentrations of large sharks occur, such as off seal colonies, near sardine and squid schools, and off river mouths. 3. Have bleeding fish in the water for any length of time. 4. Spear fishes in turbid water. 5. Stay in an area if a shark comes close and exhibits unusual swimming behaviour or a gaping display. The diver should retreat and get out of the water.

Treatment of Shark Attack Injuries

Knowledge of suitable treatment will greatly increase the likelihood of a victim's successful recovery from shark attack, as has been realized from treatment of victims in southern Africa and elsewhere. The following is an abridged version of advice given to life savers of the Surf Lifesaving Association of South Africa (SLASA):

1. Do not waste any time in recovering the victim from the water.

2. Bring the patient ashore and get him to the nearest dry area, and place him on the back with the head down and legs elevated.

3. Stop any bleeding either by pinching off arteries or by applying a tourniquet or a clean piece of cloth to the open wound to allow the blood to clot. Do not disturb this dressing by looking at the wound. Elevate the bitten limb. Check that bleeding has ceased.

4. Record the time of application of the tourniquet as it must be released an hour after application for five minutes. If a limb has been amputated do not release the tourniquet.

5. Do not rush the victim to the hospital. The patient should be given at least 30 minutes to stabilize on the beach before being moved. If possible, get a doctor to the patient. Movement of the patient before this stabilization occurs will probably result in death.

6. Comfort and reassure the patient, and check the breathing of the patient. Apply expired air resuscitation if necessary. Cover the patient with a light blanket to prevent chilling.

7. Keep control of the crowd and try and get competent paramedical or lifesaver help if a doctor is not available. These people will bring a shark attack pack to assist the patient.

8. Inform the medical people with as much information on the attack and treatment of the patient to date, including the time of attack and time elapsed since first application of a tourniquet.

Remember that shark attack is a rare phenomenon, and that the advice given above is much more likely to be of assistance in helping a victim of a car crash than of a shark attack!

Links

• International Shark Attack File

Text by Leonard J.V. Compagno, David A. Ebert and Malcolm J. Smale