Shark attack

Shark attack
A sign warning about the presence of sharks off Salt Rock, South Africa
Classification and external resources
ICD-9-CM	E906.3 E906.3

The term shark attack is used to describe an attack on a human by a shark. Every year over 70 attacks are reported worldwide. Despite their relative rarity, many people fear shark attacks after occasional serial attacks, such as the Jersey Shore shark attacks of 1916, and horror fiction and films such as the Jaws series. Out of more than 480 shark species, only three are responsible for a double-digit number of fatal, unprovoked attacks on humans: the great white, tiger, and bull;^[1] however, the oceanic whitetip has probably killed many more castaways, not recorded in the statistics.^[2]

Statistics

According to the International Shark Attack File (ISAF), between 1958 and 2016 there were 2,899 confirmed unprovoked shark attacks around the world, of which 548 were fatal.^[4]

Since 1791 to the end of 2015 Australia recorded 1,032 total shark attacks, and, is therefore, ranked as one of the highest shark attack countries worldwide. Globally, Australia is ranked the highest country in terms of shark attack fatalities, recording a total of 236 fatalities since 1791.^[5] Western Australia is also referred to as the world's deadliest waters, as the highest death rate has occurred in Western Australia, which has experienced 11 fatal shark attacks since 2000.^[6] In 2000, there were 79 shark attacks reported worldwide, 11 of them fatal.^[7] In 2005 and 2006 this number decreased to 61 and 62 respectively, while the number of fatalities dropped to only four per year.^[7] Of these attacks, the majority occurred in the United States (53 in 2000, 40 in 2005, and 39 in 2006).^[8] The New York Times reported in July 2008 that there had been only one fatal attack in the previous year.^[9] On average, there are 16 shark attacks per year in the United States with one fatality every two years.^[10] Despite these reports, however, the actual number of fatal shark attacks worldwide remains uncertain. For the majority of Third World coastal nations, there exists no method of reporting suspected shark attacks; therefore, losses and fatalities at near-shore or sea there often remain unsolved or unpublicized.

Australia has the highest number of fatal shark attacks in the world with Western Australia recently becoming the deadliest place in the world for shark attacks, which subsequently prompted a shark cull by state authorities. However, WA's 'Bait and Kill' policy was not implemented as the WA's EPA reported that the policy breached the principles of Ecological Sustainable Development; the precautionary principle, conservation of biodiversity, and inter-generational equity.^[11] Less than one in every three million scuba dives in Western Australia resulted in a fatal shark attack. This statistic is however changing after the increased popularity in personal shark deterrent devices.^[12] Nonetheless Australia and South Africa's fatality rate for shark attacks stabilised at approximately 30 percent. The United States has the highest reported number of shark attacks but has the lowest fatality rate with only around 4 percent of those attacked dying. The United States has had a total of 1,085 attacks (44 fatal) during the past 342 years (1670–2012).^[13] According to the ISAF, the states in the U.S. in which the most attacks have occurred are Florida, Hawaii, California, Texas, and the Carolinas, though attacks have occurred in almost every coastal state.^[13] South Africa has a high number of shark attacks along with a high fatality rate of 27 percent.^[14]

The location with the most recorded shark attacks is New Smyrna Beach, Florida.^[15] Developed nations such as the United States, Australia, and to some extent South Africa, facilitate more thorough documentation of shark attacks on humans than those developing coastal nations. The increased use of technology has enabled Australia and the United States to record more data than other nations, which could be somewhat bias on the results recorded. In addition to this, Individuals and Institutions in South Africa, the US, and Australia keep a file which is regularly updated by an entire research team, The International Shark Attack File, and the Australian Shark Attack File.

The Florida Museum of Natural History compares these statistics with the much higher rate of deaths from other causes. For example, an average of more than 38 people die annually from lightning strikes in coastal states, while less than 1 person per year is killed by a shark in Florida.^[16][17]

Even considering only people who go to beaches, a person's chance of getting attacked by a shark in the United States is 1 in 11.5 million, and a person's chance of getting killed by a shark is less than 1 in 264.1 million. In Australia on average one in every 5 million people is attacked by a shark, with only 1/4 of those attacked dying.^[18][19] In the United States, the annual number of people who drown is 3,306, whereas the annual number of shark fatalities is 1.^[20]

Species involved in incidents

A blacktip reef shark. In rare circumstances such as bad visibility, blacktips may bite humans, mistaking them for prey. Under normal conditions, however, they are harmless and often even quite shy.

Only a few types of sharks are dangerous to humans. Out of more than 480 shark species, only three are responsible for two-digit numbers of fatal unprovoked attacks on humans: the great white, tiger and bull;^[1] however, the oceanic whitetip has probably killed many more castaways, not recorded in the statistics.^[2] These sharks, being large, powerful predators, may sometimes attack and kill people; however, they have all been filmed in open water by unprotected divers.^[21][22] The 2010 French film Oceans shows footage of humans swimming next to sharks in the ocean. It is possible that the sharks are able to sense the presence of unnatural elements on or about the divers, such as polyurethane diving suits and air tanks, which may lead them to accept temporary outsiders as more of a curiosity than prey. Uncostumed humans, however, such as those surfboarding, light snorkeling, or swimming, present a much greater area of exposed skin surface to sharks. In addition, the presence of even small traces of blood, recent minor abrasions, cuts, scrapes, or bruises, may convince sharks to attack a human in their environment. Sharks seek out prey through electroreception, sensing the electric fields that are generated by all animals due to the activity of their nerves and muscles.

Most of the oceanic whitetip shark's attacks have not been recorded,^[2] unlike the other three species mentioned above. Famed oceanographic researcher Jacques Cousteau described the oceanic whitetip as "the most dangerous of all sharks".^[23]

Watson and the Shark by J.S. Copley, based on the attack on Brook Watson in Havana Harbor in 1749

Modern-day statistics show the oceanic whitetip shark as being seldom involved in unprovoked attacks. However, there have been a number of attacks involving this species, particularly during World War I and World War II. The oceanic whitetip lives in the open sea and rarely shows up near coasts, where most recorded incidents occur. During the world wars, many ship and aircraft disasters happened in the open ocean, and because of its former abundance, the oceanic whitetip was often the first species on site when such a disaster happened.

Infamous examples of oceanic whitetip attacks include the Nova Scotia, a British steamship carrying 1,000 people that was sunk on November 18, 1942, near South Africa by a German submarine in World War II. Only 192 people survived, with many deaths attributed to the oceanic whitetip shark.^[24] The same species is probably responsible for many of the 60–80 or more shark casualties following the torpedoing of the USS Indianapolis on July 30, 1945.^[25]

Signs warning of shark attacks at Boa Viagem Beach in Recife, Brazil

Black December refers to at least nine shark attacks on humans causing six deaths that occurred along the coast of KwaZulu-Natal Province, South Africa, from December 18, 1957, to April 5, 1958.^[26]

In addition to the four species responsible for a significant number of fatal attacks on humans, a number of other species have attacked humans without being provoked, and have on extremely rare occasions been responsible for a human death. This group includes the shortfin mako, hammerhead, Galapagos, gray reef, blacktip, lemon, silky shark and blue sharks.^[1] These sharks are also large, powerful predators which can be provoked simply by being in the water at the wrong time and place, but they are normally considered less dangerous to humans than the previous group.

On the evening of 16 March 2009, a new addition was made to the list of sharks known to have attacked human beings. In a painful but not directly life-threatening incident, a long-distance swimmer crossing the Alenuihaha Channel between the islands of Hawai'i and Maui was attacked by a cookiecutter shark. The two bites, delivered about 15 seconds apart, were not immediately life-threatening.^[27]

A great white shark is believed to be responsible for an attack on a swimmer at Muriwai Beach in Auckland, New Zealand in February 2013.^[28] It was the first confirmed shark attack fatality in the country since 1976.^[29][30]

Types of attacks

Shark attack indices use different criteria to determine if an attack was "provoked" or "unprovoked." When considered from the shark's point of view, attacks on humans who are perceived as a threat to the shark or a competitor to its food source are all "provoked" attacks. Neither the International Shark Attack File (ISAF) nor the Global Shark Attack File (GSAF) accord casualties of air/sea disasters "provoked" or "unprovoked" status; these incidents are considered to be a separate category.^[31][32] Postmortem scavenging of human remains (typically drowning victims) are also not accorded "provoked" or "unprovoked" status.^[32][33] The GSAF categorizes scavenging bites on humans as "questionable incidents."^[32] The most common criteria for determining "provoked" and "unprovoked" attacks are discussed below:

The great white shark is the first of only four species of sharks that have been involved in a significant number of fatal unprovoked attacks on humans

Provoked attack

Provoked attacks occur when a human touches a shark, pokes it, teases it, spears, hooks, or nets it, or otherwise aggravates/provokes it in a certain manner. Incidents that occur outside of a shark's natural habitat, e.g., aquariums and research holding-pens, are considered provoked, as are all incidents involving captured sharks. Sometimes humans inadvertently "provoke" an attack, such as when a surfer accidentally hits a shark with a surf board.

Unprovoked attack

Unprovoked attacks are initiated by the shark—they occur in a shark's natural habitat on a live human and without human provocation.^[31][32] There are three subcategories of unprovoked attack:

• Hit-and-run attack – Usually non-fatal, the shark bites and then leaves; most victims do not see the shark. This is the most common type of attack and typically occurs in the surf zone or in murky water. Most hit-and-run attacks are believed to be the result of mistaken identity.^[34]
• Sneak attack – The victim will not usually see the shark, and may sustain multiple deep bites. This kind of attack is often carried out with the intention of preying upon the victim; it is extraordinarily rare for this to occur and is known to happen more often in places such as South Africa where sharks are acclimated to human presence (or, worse, have learned that human presence means food due to "chumming" to lure sharks closer to the cages) due to shark cage-diving activity. Sneak attacks are the most fatal kind of attacks and are not believed to be the result of mistaken identity.^[34]
• Bump-and-bite attack – The shark circles and bumps the victim before biting. Great whites are known to do this on occasion, referred to as a "test bite", in which the great white is attempting to identify what is being bitten. Repeated bites are not uncommon, depending on the reaction of the victim (thrashing or panicking may lead the shark to believe the victim is prey), and can be severe or fatal. Bump-and-bite attacks are not believed to be the result of mistaken identity.^[34]

An incident occurred in 2011 when a 3-meter long great white shark jumped onto a 7-person research vessel off Seal Island, South Africa. The crew were undertaking a population study using sardines as bait, and the incident was judged to be an accident.^[35]

Reasons for attacks

The tiger shark is second in number of unprovoked attacks on humans.^[33]

Large sharks species are apex predators in their environment,^[36] and thus have little fear of any creature (other than orcas^[37]) with which they cross paths. Like most sophisticated hunters, they are curious when they encounter something unusual in their territories. Lacking any limbs with sensitive digits such as hands or feet, the only way they can explore an object or organism is to bite it; these bites are known as exploratory bites.^[38] Generally, shark bites are exploratory, and the animal will swim away after one bite.^[38] For example, exploratory bites on surfers are thought to be caused by the shark mistaking the surfer for the shape of prey.^[39] Nonetheless, a single bite can grievously injure a human if the animal involved is a powerful predator like a great white or tiger shark.^[40]

Despite a few rare exceptions,^[41][42] it has been concluded that feeding is not a reason sharks attack humans. In fact, humans don't provide enough high-fat meat for sharks, which need a lot of energy to power their large, muscular bodies.^[39]

Sharks normally make one swift attack and then retreat to wait for the victim to die or exhaust itself before returning to feed. This protects the shark from injury from a wounded and aggressive target; however, it also allows humans time to get out of the water and survive.^[43] Shark attacks may also occur due to territorial reasons or as dominance over another shark species, resulting in an attack.^[44]

Sharks are equipped with sensory organs called the Ampullae of Lorenzini that detect the electricity generated by muscle movement;^[45] another theory is that the shark's electrical receptors, which pick up movement, pick up the signals like those emitted by wounded fish from someone who is fishing or spearfishing, and thus attack the person by mistake.^[44]

George H. Burgess, director of the International Shark Attack File, said the following regarding why people are attacked: "Attacks are basically an odds game based on how many hours you are in the water".^[46]

The bull shark is the third in statistics of unprovoked attacks on humans.^[33] They are found in freshwater rivers and lakes as well as the ocean.^[47]

Protection

Shark nets

In Australia and South Africa shark nets are used to reduce the risk of shark attack. Since 1936 sharks nets have been utilsed off Sydney beaches.^[48] Nowadays they are employed on both NSW and Queensland beaches; 83 beaches are meshed in Queensland compared with NSW's current 51.^[48][49] Since 1952 numerous beaches in South Africa are protected by the KwaZulu-Natal Sharks Board.

Shark nets do not offer complete protection but work on the principle of "fewer sharks, fewer attacks". They reduce occurrence via shark mortality. Reducing the local shark populations is believed to reduce the chance of an attack. Historical shark attack figures suggest that the use of shark nets and drumlines does markedly reduce the incidence of shark attack when implemented on a regular and consistent basis.^[50]

The downside with sharknets is that they do result in bycatch, including threatened and endangered species.^[51]

Drumlines

A drum line is an unmanned aquatic trap used to lure and capture large sharks using baited hooks. They are typically deployed near popular swimming beaches with the intention of reducing the number of sharks in the vicinity and therefore the probability of shark attack. Drum lines were first deployed to protect users of the marine environment from sharks in Queensland, Australia in 1962. During this time, they were just as successful in reducing the frequency of shark attacks as the shark nets^[52] More recently, drumlines have also been used with great success in Recife, Brazil where the number of attacks has been shown to have reduced by 97% when the drumlines are deployed.^[53] While shark nets and drum lines share the same purpose, drum lines are more effective at targeting the three sharks that are considered most dangerous to swimmers: the bull shark, tiger shark and Great white shark.^[54]

Protection by dolphins

The oceanic whitetip has made many attacks on survivors of shipwrecks or downed aircraft; these are difficult to confirm and are rarely included in shark attack indices.^[33][55]

There are documented instances of bottlenose dolphins protecting humans from shark attacks, such as one attack on a surfer in northern California in August 2007^[56] and one off the coast of New Zealand in 2004.^[57] There is no accepted explanation for this behavior; as mentioned in the Journal of Zoology, "The importance of interactions between sharks and cetaceans has been a subject of much conjecture, but few studies have addressed these interactions".^[58] In some cases, sharks have been seen attacking, or trying to attack dolphins.^[59] The presence of porpoises does not indicate the absence of sharks as both eat the same food.^[60]

Media impact

The effect the media has on the population's view of shark attacks has generally been negative. Starting with the effects generated from news broadcasts, a shark attack is quickly broadcast across the country, particularly if fatal, even though more people die from random occurrences such as lightning strikes than from a shark attack.^[61]

The Jersey Shore shark attacks of 1916 killed 4 people in the first 2 weeks of July 1916 along the New Jersey shore and Matawan Creek in New Jersey. They are generally credited as the beginning of media attention on shark attacks in the United States of America.^[62]

In 2010 nine Australian survivors of shark attacks banded together to promote a more positive view of sharks. The survivors made particular note of the role of the media in distorting the fear of sharks.^[63] Films such as Jaws were the cause of large-scale hunting and killing of thousands of sharks.^[64] There are some television shows, such as the famous Shark Week, that are dedicated to the preservation of these animals.^[65] They are able to prove through scientific studies that sharks are not interested in attacking humans and generally mistake humans as prey.

List of notable victims

• George Coulthard (1856–1883), Australian cricketer and Australian rules footballer
• Mick Fanning (1981–), Australian surfer
• Rodney Fox (1940–), Australian filmmaker and conservationist
• Bethany Hamilton (1990–), American surfer

• Brook Watson (1735–1807), British soldier and mayor

Notable fatal victims

• Shirley Ann Durdin, torn in half, killed and consumed by a great white shark in 1985 in South Australia^[66]
• Nick Peterson, torn in half and eaten by two great white sharks on December 16th, 2004 in South Australia^[67][68][69]
• Lloyd Skinner, eaten alive by a great white shark on January 12th 2010 in Fish Hoek, Western Cape, South Africa; the shark was described being "as large as a dinosaur"^[70]
• Mathieu Schiller (1979-2011), French bodyboarder who was killed at Saint-Gilles, Réunion in 2011; he was killed by a shark believed to be a tiger shark or a bull shark, and his body was not recovered.^[71][72]
• Sam Kellett, eaten alive by a great white shark in 2014 in South Australia;^[73][74] after his death his family said he would've opposed the Western Australian shark cull if he had lived^[75]

See also

References

External links

• International Shark Attack File
• Global Shark Attack File — Open database
• Peoples Shark Attack File — Online Searchable Open database
• Australian Shark Attack File
• Australasian Shark Attack File — Open database
• Shark Attack Survivors — Shark attack education and prevention
• Shark attack information, statistics, and pictures
• Swim At Your Own Risk — Shark attack news and photos
• Shark Attack News — Shark news, videos & pics
• Shark Attack Data — Database of shark attacks, based on the Shark Research Institute's Global Shark Attack File