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International Shark Attack File

Diving with elasmobranchs: a call for restraint
George H. Burgess, Florida Museum of Natural History, USA
First published July 1998 by the IUCN/SSC Shark Specialist Group in Shark News 11

Introduction

As curator of the International Shark Attack File, I have a special interest in shark/human interactions and have followed closely the development of ecotourism dive operations involving elasmobranchs. Most prevalent are attractions involving the feeding of sharks.

At least three types of shark feeding operations occur. Metal or PVC shark cages are used mainly in white shark Carcharodon carcharias dives at numerous locations worldwide; also by blue shark Prionace glauca and reef shark Carcharhinus spp. feeding attractions in California and Australia, respectively. Chain mail suits (no cages) are utilized by other operations largely targeting blue sharks (e.g. in California) but also in at least one Bahamas carcharhinid dive.

feeding grey reef sharks Carcharhinus amblyrhynchos
Shark feeding operations provide the best opportunity for most divers to see sharks close at hand, in the wild. These are grey reef sharks in the Red Sea.
Photo J. Stafford-Deitsch.

Finally, many feeding operations do not provide tourists with any protective gear (Bahamas, Florida, Maldives, and probably other localities). The common denominator in all operational types is chumming or baiting. Some go so far as to promote hand-feeding of sharks or even to 'train' their clients in hand-feeding techniques.

Non-feeding observation dives with whale sharks Rhincodon typus, basking sharks Cetorhinus maximus, and manta rays (Mobulidae) and stingray (Dasyatidae) feeding operations also take place.

Shark feeding

My reservations about feeding-type dives are based on four interrelated factors: the safety of the divers; the likelihood for negative publicity directed at sharks if a shark bites a diver during one of these dives; the possibility for ecological disruption; and potential negative impact on multi-user recreational use of the feeding area.

Diver safety

Shark cage diving generally appears to be safe. I am unaware of any serious injuries to divers, excepting biting wounds to hands placed outside the cage. Chain mail and no-protective-gear dives have resulted in injury to participants. Chain mail suits offer protection only from small to medium-sized sharks. However, the tooth tips of even small sharks can penetrate the mesh resulting in injury - well documented in the much-replayed video involving Valerie Taylor. The powerful jaws of larger sharks may produce crushing injuries even if teeth do not penetrate the mail. A large shark with serrated, shearing teeth, e.g. a white, tiger Galeocerdo cuvier, bull Carcharhinus leucas, or dusky Carcharhinus obscurus, would likely be able to cut through such mesh. The metal mail may even be electromagnetically attractive; white sharks, in particular, are well documented biters of metal ship hulls and propellers.

In the Bahamas, where unprotected dive-with-sharks operations developed quickly as a tourist draw, more than a dozen injuries have occurred in the last several years, at least two quite serious. Most were not publicized because of efficient damage control by local operators. Perhaps fortunately for the operators, most victims were host dive masters, but a serious injury to a diving tourist is inevitable.

Last year I took part in an unprotected Bahama feeding dive to view its design and safety. The experience was exhilarating. An aggregation of about 50 sharks (blacktip Carcharhinus limbatus, Caribbean reef C. perezi, and nurse Ginglymostoma cirratum) were attracted to a frozen fish 'chum ball' at a site utilised continuously (3-4 times a week) for several years. Hundreds (thousands?) of bony fishes were similarly attracted. I did not feel threatened by the sharks swimming above and around me as we knelt on the sand bottom of a natural 'amphitheatre.' I did note one blacktip, apparently low in a dominance order, confined to the perimeter of the circling mass of fishes and reluctant to approach the central chum ball. It exhibited apparent displacement or frustration behaviour: periodic mouth gaping, increasing over time, and occasional erratic swimming movements, including back hunching and pectoral fin dropping. This type of behaviour has been observed immediately prior to attacks on divers at other Bahamas shark feeding dive sites, and is similar to gray reef shark behavior observed by Nelson et al. (1986) in the Pacific.

To reduce risk of shark attack:

  • avoid diving in an area known to be frequented by sharks
  • avoid diving in waters known to contain animal carcasses and blood
  • avoid wearing shiny objects and contrasting colors while diving do not touch sharks

An unanswered question is whether individual bait-entrained sharks are more or less dangerous to humans than their wild peers. Observations of feeding reef sharks in the Bahamas, which largely ignore divers, could suggest 'no more' or even 'less' of a threat. However, shark attack rate is profoundly influenced by the concentrations of sharks and humans occupying the water at the same time. Increases in either generally result in an increased probability of an attack. Obviously, high concentrations of both sharks and humans are found together in a small area in baited-shark dives. It is also clear that sharks attracted to bait are in a heightened state of excitement, some approaching or achieving frenzy. In addition, the unnaturally high concentrations of sharks pursuing a limited resource (the bait) may lead to increases in density-dependent agonistic behavioural displays (see box above) and increased likelihood of attack. Furthermore, we do not know how the food-conditioned sharks behave when the free food stops. Recently a documented attack occurred on a diver swimming at a Bahamas feeding site on a non-feeding day.

Many dive operations actually encourage ecotourists to touch the sharks. At least one offers "shark feeding instruction." Such ill-considered activity promotes irrational human behaviour like that prominently displayed in a recently published US dive magazine devoted to diving with sharks. The cover depicts a diver holding a 2-2.5m Carcharhinus, hands on snout and dorsal fin. A photograph accompanying one story ("Friendly Encounters") captures a diver grabbing a ride on the tail of a "16ft" white shark. Another article ("Cool and Cuddly Sharks") is accompanied by photos of divers hugging sharks. I am not a shark attack alarmist - at the ISAF we have consistently tried to put attack in perspective and turn media attention to more important conservation-based shark issues - but we cannot ignore the fact that sharks are wonderfully designed predators that can and occasionally do harm humans. While some entrained sharks can be approached and even handled readily, do we want to send the message that divers routinely can approach, touch, and even hug sharks in other situations? I can't think of any situation where grabbing the tail of a 16ft white shark is advisable.

The recent rise in the number of inshore baited white shark dives has raised a serious concern: will these operations attract a larger number of white sharks into the area, resulting in an increased probability of attack (and potentially serious trauma and fatality) on other user groups operating there? Whites are a more serious threat to humans than most carcharhinids - they are larger and normally consume larger prey. I believe a short-term localised increase in their number is a real possibility; with that increase comes a greater chance of whites and humans interacting.

Ecotourism dives aside, shark attacks on humans are rare. Nevertheless, shark attack still is of great interest and concern to the public. The ISAF routinely provides advice on how to reduce the already tiny chance of attack. It is ironic that shark-feeding dives freely violate several of the axioms of conventional wisdom advocated by virtually all attack researchers (see box above). That more than two dozen reported attacks have occurred worldwide during shark feeding comes as no surprise to those who study shark attack.

Media hype

If safety of participants was the only concern, I would not object to shark feeding dives, assuming, of course, that divers are duly forewarned that injuries have occurred and that the sport carries an inherent risk (currently, many operations maintain bites have not occurred anywhere). Any injury or fatality then could be rationalised as an unfortunate accident. However, when such a serious attack does occur - and I predict unequivocally that it will - media coverage will be tremendous. The tabloid press predictably will hype a story involving a diving tourist who loses a hand or arm during one of these operations. Imagine what reaction a fatality will bring! Actual video of the incident is likely to be available to tabloid television as these dives are routinely taped by host dive operators and participants alike. Needless to say, the shark will not be portrayed favourably - the "Jaws" image will be reinforced ad nauseam. The recently reshaped, biologically accurate public image of sharks that many have worked so hard to foster will be undercut quickly and decidedly.

Ecological disruption

This is of equal concern in the shallow-water shark-feeding areas, where the feeding operations are altering the natural system. Based on my personal dive experience and those of others, it is clear that the concentrations of sharks and bony fishes at feeding sites are unnatural. It is normally difficult to see blacktip or reef sharks in non-feeding situations in the Bahamas; they tend to avoid divers, are quite skittish, and (except for nurse sharks) are rarely encountered while diving (unless spearfishing).

The lure of the feeding operations, of course, is the guarantee of success in giving divers a chance to see and
grey reef shark Carcharhinus amblyrhynchos and diver
Gray reef shark Carcharhinus amblyrhynchos during a shark feeding dive.
photograph sharks which are largely oblivious to the divers. However, the resident sharks and some bony fishes at these sites are now trained 'show animals' and at least partially dependent on free food.

That the Bahamas sharks are indeed entrained is demonstrated by their response to the sound of boat motors. Dive operators routinely rev their engines as they approach the feeding site in order to attract the sharks, which rapidly arrive, surrounding the boat long before the first food or diver hits the water (sound Pavlovian?). Similar entrainment has been reported at Australian feeding sites.

Groupers (Serranidae) at some Caribbean and Bahama feeding sites are similarly well-trained, rising from the reefs in search of handouts from divers entering the water. At Grand Cayman, where diver feeding of reef fishes was fashionable for years, I observed mushrooming populations of sergeant-major Abudefduf saxatilis and yellowtail snapper Lutjanus chrysurus. They became pests at feeding sites, hovering around divers looking for handouts (and in the case of sergeant-majors, frequently biting divers' fingers).

The highly migratory nature and differing reproductive strategies of Carcharhinus spp. prevents direct analogy to these situations, but it seems possible that their population size is increasing locally at feeding sites. We do not know if such local concentration of sharks at feeding sites allows natural levels of density and distribution to be maintained over adjacent areas. Alternatively, the feeding sites may simply relocate sharks from nearby areas and overall populations may be stable or even in decline. No hard data are available, but the large numbers congregating around feeding sites indicate that repetitive feeding attracts sharks from wide distances. Feeding may promote higher than normal local shark population levels since food is readily obtainable at virtually no energetic cost. Additionally, localised clustering of sharks and associated bony fishes entrained to feeding may present an easy mark for poachers, as it did in the Bahamas when rogue fishers wiped out a local aggregation of sharks associated with a shark-feeding attraction.

Conversely, while some operations use otherwise discarded remains of recreationally caught fishes as bait, others obtain chum or bait fishes by spearfishing. Localised depletion of reef-fishes may occur in these areas. Some South African white shark dive operators reportedly catch juvenile bronze whaler Carcharhinus brachyurus and smooth hammerhead Sphyrna zygaena sharks to use as bait. As with reef-fishes, repetitive fishing for these species in a small area may lead to reductions in local populations.

Impacts on other water users

The presence of sharks entrained to the sound of a motor may lead to localised loss of multi-party recreational activities such as fishing, spearfishing, and traditional skin or SCUBA diving where divers are not interested in encountering sharks en masse. If sharks appear whenever a motorboat visits a region, anglers are likely to lose their hooked catches to opportunistic sharks or have the sharks frighten away potential catches. Skin and SCUBA divers seeking sharkless diving will encounter unwelcome escorts. As noted above, a tourist diving at a feeding site on a non-feeding day was bitten on the head by a carcharhinid shark. We have heard of a diver who had a shark follow his outboard motor-driven boat from dive stop to dive stop, eventually ending in a bite.

I am of the opinion that inshore feeding of sharks is not in the best long-term interest of an area's economy. While the activity will draw in ecotourists, inevitably a serious shark bite will occur, producing significant trauma or death. The ensuing negative publicity likely will result in the loss of that segment of tourists as well as at least some others who do not wish to meet sharks regularly during their dives.

Pelagic shark-feeding cage operations may be of less consequence than inshore unprotected dives. The feeding sites generally are located far away from centres of human activity, entrainment of the sharks is less likely, and the ecotourists are adequately protected.

Whale sharks, basking sharks and mantas

Whale shark and manta ray ecotourism dives have appeared recently, primarily in the Indo-Pacific. Basking shark ecotourism has potential in some temperate waters. Activities focusing on these large planktivores raise some of the same concerns historically directed at ecotourism operations targeting whales; that the natural behaviours of these species will be altered by the proximity of divers and boats, and possibly spotter airplane noise and shadows. Strict regulations address observation and harassment of marine mammals, and stipulate specific separation requirements in the USA. In contrast, 'riding' whale sharks and mantas is shown in some magazine photographs and television videos and evidently is viewed as a desirable activity by some. This situation has been addressed in Western Australia (see article "Whale shark management programme, Western Australia"), where human-whale shark interactions are now managed and monitored. The development of similar protocols elsewhere would be prudent.

Stingray feeding

This does not appear to be of such concern, although there is some potential for injury where it occurs (several localities in the Caribbean and Maldives, and perhaps elsewhere). Video footage of a shallow-water feeding operation in the Virgin Islands shows numerous large Dasyatis americana swimming amongst and through the legs of tourists standing in waist deep water, knocking some off their feet. It is likely that a large spine will be encountered sometime during a fall. The 'media image' problem, however, is not likely to arise, nor are there concerns over multi-user recreation. Ecological disruption is probably minimal.

Conclusions

Dive-with-sharks operations have been lauded as a positive environmental experience for those divers who can afford this activity and vicariously for thousands of television viewers of documentaries and dive programs. Certainly allowing many people to see sharks in situ is good publicity for these animals and helps to dispel the 'man-eater' stereotype. But are entrained sharks performing on cue really exhibiting any more natural behaviour than we see in trained circus animals? Does swimming in circles and gnawing on a frozen 'chum ball' or taking bait fishes off a spear or out of the hand or mouth of a human constitute 'sharks in the wild'? Public aquaria offer basically the same view of sharks without fostering the 'eating machine' image enhanced by frenzied feeding.

It appears that the pendulum has completely swung as a newly restructured shark image emerged in the shark-feeding dive community. Sharks have been transformed from being blood-thirsty man-eaters to playful puppies by some of those most closely tied to shark-feeding operations. As often is the case, the truth lies somewhere in between these two extremes. Based on the safety, ecological, social and conservation considerations noted above, I believe that scientific/ conservation endorsement of most shark-feeding attractions is unwise. On balance, it appears that sharks have more to lose than to gain by these operations.

Acknowledgements

I thank Matthew Callahan, Kevin Johns, Robert Robins and Franklin Snelson for providing constructive comments on this contribution.

Reference

Nelson, D.R., Johnson, R.R., McKibben, J.N., and Pittenger, G.G. 1986. Agonistic attacks on divers and submersibles by gray reef sharks, Carcharhinus amblyrhynchos: antipredatory or competitive? Bull. Mar. Sci. 38(1): 68-88.

George H. Burgess,
Florida Museum of Natural History,
University of Florida,
Gainesville, FL 32611, USA
Email:
gburgess@flmnh.ufl.edu

PDF of original article first published 1998 in SHARK NEWS