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Shark attack

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For the film, see Shark Attack (film).
A sign warning about the presence of sharks off Salt Rock, South Africa.

A shark attack is an attack on humans by sharks. Every year, a number of people are attacked by sharks, although death is quite unusual. Despite the relative rarity of shark attacks, the fear of sharks is a common phenomenon, having been fueled by the occasional instances of attacks, such as the Jersey Shore shark attacks of 1916, and by horrific fiction and film, such as the Jaws series. Many shark experts feel that the danger presented by sharks has been exaggerated, and even the creator of the Jaws phenomenon, the late Peter Benchley, attempted to dispel the myth of sharks being man-eating monsters in the years before his death.

Statistics

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

In 2000, the year with the most recorded shark attacks, there were 79 shark attacks reported worldwide, 16 of them fatal[1]. In 2005 and 2006 this number decreased to 61 and 62 respectively, while the number of fatalities dropped to only four per year[1]. Of these attacks, the majority occurred in the United States (53 in 2000, 40 in 2005 and 39 in 2006)[2]. The New York Times reported in July 2003 that there had been only one fatal attack in the previous year.[3]

The United States has had more shark attacks (1,032) than any other country[4]. According to the International Shark Attack File, the states in the U.S. where the most attacks have occurred are Florida, Hawaii, California, South Carolina and North Carolina[4]. Outside the U.S., Australia and South Africa have had the most attacks[5]. As of 2009, the ISAF recorded a total of 2,251 attacks worldwide since 1580, with 464 attacks being fatal[5]. The location with the most recorded shark attacks is New Smyrna Beach, Florida[6].

The Florida Museum of Natural History compares these statistics with the much higher rate of deaths from other, less feared causes; for example, several thousand people die annually from lightning strikes[7]. It is estimated that a person's chance of getting attacked by a shark is 1 in 11.5 million, and a person's chance of getting killed by a shark is 1 in 264.1 million[8]. The annual number of people who drown is 3,306, whereas the annual number of shark fatalities is 1[9]. In comparison, humans kill 100 million sharks each year[10].

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.

Contrary to popular belief, only a few sharks are dangerous to humans. Out of more than 360 shark species, only four have been involved in a significant number of fatal unprovoked attacks on humans: the great white, tiger, bull[11] and the oceanic whitetip[12]. These sharks, being large, powerful predators, may sometimes attack and kill people; however, they have all been filmed in open water by unprotected divers.[13][14] The 2010 French film Oceans (2010 film) by Jacques Perrin is the film that shows footage of human swimming next to sharks deep in the ocean. Most of the oceanic whitetip shark's attacks have not been recorded[12], unlike the other 3 species mentioned above.

Watson and the Shark by J.S. Copley, based on an attack on a swimmer in Havana 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 due to 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 sinking of the Nova Scotia, a steamship carrying 1000 that was sunk near South Africa by a German submarine in World War II. Only 192 people survived, with many deaths attributed to the oceanic whitetip shark.[15] Another example was the torpedoing of the USS Indianapolis on 30 July 1945, giving a minimal figure of 60–80 killed by oceanic whitetips.[16] Some survivors stated that tiger sharks were involved too.

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 reef, lemon, silky, and blue sharks.[11] 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 divers and swimmers than the previous group. A few other shark species do attack people every year, producing wounds that can potentially kill, but this occurs either specifically because they have been provoked, or through mistaken identity due to water conditions or the like.

Types of attacks

Scientists have defined 2 types of shark attacks (one of which has 3 subcategories)[17]:

  • Provoked attack - the human touches the shark
  • Unprovoked attack
    • Hit-and-run attack - usually non-fatal, the shark bites and then leaves
    • Sneak attack - deep water attack, can be fatal
    • Bite-and-bump attack - the shark bumps before biting

Reasons for attacks

While one should be very cautious with great white sharks, they do not target humans as prey.

Sharks are apex predators in their environment[18], and thus have little fear of any creature they cross paths with. 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[19]. Generally, shark bites are exploratory, and the animal will swim away after one bite[19]. For example, exploratory bites on surfers are thought to be caused by the shark mistaking the surfer for the shape of prey[20]. Nonetheless, a single bite can grievously injure a human if the animal involved is a powerful predator like a great white or tiger shark[21].

Despite a few rare exceptions[22] [23], it has been concluded that feeding is not a reason sharks attack humans; as stated on Howstuffworks.com, "Humans are not on the menu. In fact, humans don't provide enough high-fat meat for sharks, which need a lot of energy to power their large, muscular bodies"[20].

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[24]. Shark attacks may also occur due to territorial reasons or as dominance over another shark species, resulting in an attack[25].

Sharks are equipped with sensory organs called the Ampullae of Lorenzini that detect the electricity generated by muscle movement[26]; another theory is that the shark's electrical receptors, which pick up movement, pick up the wounded signals of fish from someone who is fishing or spearfishing, and thus attack the person by mistake[25]. Great white sharks can also smell blood in saltwater, even at a ratio of 0.16 oz per 3.3 cu. ft (5 ml per 1 m3).

George 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"[27].

Prevention

While there is no way to completely eliminate the possibility of a shark attack when you are in the water, here are some precautions you may take to reduce that risk[28]:

  • Avoid the water at dawn, dusk, or night, when sharks tend to feed.
  • Avoid areas where sharks generally locate themselves, such as murky waters and steep drop-offs.
  • Avoid bleeding.
  • Don't swim alone, always be near a group of people, and if possible, avoid being at the edge of the group.
  • Obey instructions from lifeguards and other authority.
  • Most importantly, use common sense, remember that all sharks (even ones we consider "harmless") are wild animals and there is no way of us knowing for sure how these creatures will react. Always respect what they are capable of doing, and be wary.

Dolphins' protection

There are many documentations of dolphins protecting humans from shark attacks, such as an attack on a surfer in northern California in August 2007[29]. It was also documented off the coast of New Zealand in 2004[30]. Typically, dolphins form a ring around humans who are injured[29]. However, in spite of years of scientific study, there has been no conclusive explanation given 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"[31]. In some cases, sharks have been seen attacking, or trying to attack dolphins[32]. As stated by ISAF: "Remember that sightings of porpoises do not indicate the absence of sharks — both eat the same food"[33].

See also

References

  1. ^ a b http://www.flmnh.ufl.edu/fish/Sharks/statistics/statsw.htm
  2. ^ http://www.flmnh.ufl.edu/fish/sharks/statistics/statsus.htm
  3. ^ The New York Times http://www.nytimes.com/2008/07/29/scie. {{cite news}}: Missing or empty |title= (help)
  4. ^ a b http://www.flmnh.ufl.edu/fish/sharks/statistics/GAttack/mapusa.htm
  5. ^ a b http://www.flmnh.ufl.edu/fish/sharks/statistics/GAttack/World.htm
  6. ^ USA Today. 21 April 2008 http://www.usatoday.com/travel/news/2008-04-18-shark-beaches-forbes_N.htm. Retrieved 9 April 2010. {{cite news}}: Missing or empty |title= (help)
  7. ^ Florida Museum of Natural History, University of Florida. A Comparison with the Number of Lightning Fatalities in Coastal United States: 1959-2006
  8. ^ http://www.oceana.org/?id=2074
  9. ^ http://www.flmnh.ufl.edu/fish/sharks/attacks/relarisklifetime.html
  10. ^ http://animals.howstuffworks.com/fish/shark-fishing.htm
  11. ^ a b ISAF Statistics on Attacking Species of Shark
  12. ^ a b http://animals.howstuffworks.com/fish/most-dangerous-shark2.htm
  13. ^ Hawaiian newspaper article
  14. ^ The 1992 Cageless shark-diving expedition by Ron and Valerie Taylor.
  15. ^ Bass, A.J., J.D. D'Aubrey & N. Kistnasamy. 1973. "Sharks of the east coast of southern Africa. 1. The genus Carcharhinus (Carcharhinidae)." Invest. Rep. Oceanogr. Res. Inst., Durban, no. 33, 168 pp.
  16. ^ Martin, R. Aidan. "Elasmo Research". ReefQuest. Retrieved 6 February 2006. {{cite web}}: Unknown parameter |dateformat= ignored (help)
  17. ^ http://www.flmnh.ufl.edu/fish/education/questions/attack.html
  18. ^ http://na.nefsc.noaa.gov/sharks/
  19. ^ a b http://www.romow.com/travel-blog/what-to-expect-on-your-great-white-shark-diving-tour/
  20. ^ a b http://adventure.howstuffworks.com/shark-attack.htm
  21. ^ http://adventure.howstuffworks.com/shark-attack4.htm
  22. ^ http://www.dailymail.co.uk/travel/article-593058/Shark-attack-tears-teenager-two.html
  23. ^ http://www.dailymail.co.uk/news/article-1102086/Shark-spotted-body-man-jaws-witnesses-look-horror.html
  24. ^ http://www.extremescience.com/GreatWhiteShark.htm
  25. ^ a b http://adventure.howstuffworks.com/shark-attack1.htm
  26. ^ http://www.marinebiodiversity.ca/shark/english/ampul.htm
  27. ^ "Shark attacks at record high". BBC News. 9 February 2001. Retrieved 6 April 2010.
  28. ^ http://www.flmnh.ufl.edu/fish/sharks/Attacks/relariskreduce.htm
  29. ^ a b http://www.msnbc.msn.com/id/21689083/
  30. ^ "Dolphins prevent NZ shark attack". BBC News. 23 November 2004. Retrieved 6 April 2010.
  31. ^ http://www3.interscience.wiley.com/journal/119027448/abstract?CRETRY=1&SRETRY=0
  32. ^ http://www.abcactionnews.com/news/local/story/Rehabilitated-dolphin-dies-after-shark-attack/Os5uEUUiFU2NukbdnqiZXQ.cspx
  33. ^ http://www.ncseagrant.org/home/coastwatch/coastwatch-articles?task=showArticle&id=570
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