Great White Shark information

The White Shark – Carcharodon carcharias

The White Shark belongs to the family Lamnidae and is closely related to the Mako, Porbeagle and Salmon Sharks.

It’s scientific name is Carcharodon carcharias and is more commonly known as the White Shark, Great White and White Pointer. The White Shark can reach lengths over 6 metres and can weigh up to 3,000 kilograms.

See the fact sheets for information on:

  • Distribution Biology - diet, snout, heat, eyes, electro reception, maturity and reproduction.
  • Protection Status
  • Supporting data for protection
  • Threats - Both major and minor
  • Tagging
  • Shark attack statistics

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The White Shark – Carcharodon carcharias

 

The White Shark belongs to the family Lamnidae and is closely related to the Mako, Porbeagle and Salmon Sharks. It’s scientific name is Carcharodon carcharias and is more commonly known as the White Shark, Great White and White Pointer. The White Shark can reach lengths over 5 metres and can weigh up to 2,000 kilograms.

 

DistributionIt has been recorded that the distribution of White Sharks are widespread across Australia, New Zealand, Sth Africa, the Mediterranean and Red Seas, Northern coasts of France and Spain, Portugal, NW coast of Africa, Japan, Chile, Nth America mostly off the coast of California. White Sharks range in temperate oceans and are sometimes found in the tropics (Fergusson, 1998). They are common in coastal and shelf waters, especially those inhabited by fur-seal colonies and other pinnipeds. According to Fox Shark Research Foundation (FSRF) the White Shark seems to prefer waters with a temperature of 15-22 degrees C although it has been recorded in waters with temperatures between 4-27 degrees C. (FSRF 2004)

Map of distribution sourced at http://www.cmar.csiro.au/research/sharks/whitesharks/global.html

 

Biology

 

Diet

 

Adult White Sharks are known to have a diet of fish, such as snapper, mackerel and tuna, they also eat other sharks, dolphins, and marine mammals, such as sea lions and fur seals. White Sharks have been recorded to surface to feed on floating whale carcasses. The main prey in South Australian waters are the Australian Sea-Lion and New Zealand Fur Seals. The seals are large and rich in blubber therefore the White Shark feeds on mammal prey infrequently. (FSRF 2004)

 

Snout

 

A shark smells with tiny structures called “lamellae”. The lamellae are located near the tip of its snout in two nostrils and are so sensitive that they can detect one part of blood in ten billion parts of water (FSRF 2004).

 

Heat

 

The White Shark is warm bodied; by using a process named regional endothermy the shark is able to elevate parts of its body above that of the ambient water temperature. Through a counter-current heat exchange system, the temperature in the stomach, brain, eye and swimming muscles can be up to 13 °C higher than its surroundings (Goldman, 1997) with its stomach remaining at about 25°C (Goldman 1997). This can be extremely advantageous for the shark, allowing the shark to accelerate its speed and have more powerful attacks on prey (Goldman 1997).

 

Eyes

 

White Sharks rely heavily on vision to seek prey and provide other information on it’s surrounding environment. To protect its eyes from injury during a predatory attack the White Shark rolls its eyes tail ward in their sockets. This exposes a tough, fibrous sclerotic coat that protects the eyes while the prey is shaken in its jaws. The shark is temporarily blinded at the moment of strike. The eyes of White Sharks are also extremely sensitive and are able to magnify the amount of available light. This is done by the tapetum lucidum, a shiny layer of plates that reflects light back on to the retina, similar to that of cats, and can be covered when surfacing to prevent damage. (Martin NDb)

 

Electro reception

 

It is known that the White Shark has electro reception, which is an acute sensitivity to electrical fields. Electro reception may assist in capturing prey, as the shark is temporarily blind at the moment of strike it may rely on electrical cues to keep track of its prey. (Martin NDa)

 

Maturity and Reproduction

 

Females mature at between 4.5-5.0 metres and at around 18 years old. Males mature at about 3.6-3.8 metres and 10 years old. (Malcolm et al. 2001) Female White Sharks only reproduce every 2-3 years; and the gestation period can exceed 12 months possibly even 18 months. Litter sizes have been recorded between 2-10 pups per litter. The reproductive mode in White Sharks is aplacental viviparity with the embryos being nourished by oophagy. Oophagy is when the embryos are nourished by eggs ovulated from the mother’s ovary.

Longevity is unknown but considered to be in excess of 30 years.

 

Protection status

 

The White Shark is listed as vulnerable on the IUCN Red list of Threatened species. (ICUN 2006) In 2004 the White Shark was CITES (Convention on International Trade in Endangered Species of Fauna and Flora) protected. This means that a permit is needed to trade in any part of the white shark.

In 1996 NSW declared the White Shark a protected species making it an offence to kill a shark, with a possible $20,000 fine and up to 6 months jail sentence. In December 1997 Australia declared the protection on the White Shark under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999), prohibiting hunting and harassment of the species in Commonwealth waters. The White Shark is fully protected in South Australia, Victoria, Tasmania, and commercially protected in Western Australia. It is also protected in New South Wales and Queensland however there are exemptions for accidental catches in beach meshing. (FSRF 2004)

 

Supporting data for protection

 

Globally, there has been a reported decline of between 60-95% in White Shark numbers in the last 50 years (Reid & Krogh 1992). A decline can be seen in several studies and reports. Supporting data, for the declining White Shark population and the need for protection, can be found in data sets from shark control programs in NSW and QLD, game fishing records in SA and NSW, sighting reports in SA, and international reports (Reid &Krogh 1992, Krogh 1994). Reports of catches from commercial fishing in NSW have also changed from large adults to juveniles and also suggest a decline in numbers. Tourism operators have reported a decline in sighting frequencies in SA. (DEH 2002)

Pepperell (1992) using game fishing data for NSW calculated that the ratio of White Sharks to all shark species caught had changed from 1:22 in the 60’s to 1:38 in the 70’s and 1:651 in the 1980’s. The decline in numbers is also reflected by sport fisheries data on eastern United States, where the proportion of Great White Sharks taken relative to other shark species dropped from 1:67 in 1965 to 1:210 in 1983. (Casey and Pratt 1985, DEH 2002)

The vast majority of White Sharks caught in recent years have been juveniles or perhaps adolescents (Krogh 1994). The reduction of mature adults present can mean disastrous effects on the White Shark population. It is known that the species has a slow growth rate, late maturity, low fecundity and long gestation (FSRF 2004). The reduction of breeding adults suggests that the species is under threat and population recovery will be extremely slow (DEH 2002).

 

Threats

 

Commercial fishing

 

White Sharks are taken as by-catch in nets and on long lines by commercial fishers. Estimates of annual capture, based on anecdotal reports, range from less than 10 to 100 per annum in SA (Bruce 1992). The mortality rate of the White Shark is difficult to determine as many commercial fisheries out of Australia do not have requirements to report catches of White Sharks. The reporting of interaction with White Sharks must be improved by commercial fisheries. About 40% of captured White Sharks are released alive although post release survival rates are unknown.

 

Recreational fishing

 

Game fishing of the White Shark was carried out in SA, QLD, NSW and to a lesser degree in VIC and WA before protective legislation was brought about (FSRF 2004). Game fishing groups have expressed an interest in accessing white sharks for tag-release since the species was protected. Regulatory authorities must grant an exemption permit to re-instate tag-release in recreational fishing. There would have to be scientific benefits for such permits to be granted. (DEH 2002)

 

Shark Control Activities

 

Beach meshing is used as a protective measure for swimmers, divers, and surfers against shark attacks. There are three major beach meshing shark control programs. One program is located in KwaZulu-Natal in South Africa (and run by the Natal Sharks Board) and two programs are located in Australia in NSW and QLD (Krogh & Reid 1996).

Shark nets do not completely enclose beaches but are usually 150 metres long and 6 metres high, with a mesh size of 50 to 60cm (Krogh 1994). The nets are set parallel to the shore in around 10-15m depth with the bottom resting on the ocean floor and the top supported by a series of floats (Krogh 1994). White Sharks caught by beach meshing programs are usually small with over 98% being under 4 metres in length (total length) indicating that the nets may be close to pupping grounds (Krogh 1994). There has been a decline of White Sharks captured in NSW meshing since 1950 (Reid & Krogh 1992).

Non-target species that are captured in the shark nets include whales, dugongs, turtles, and dolphins (Dudley & Gribble 1999). The impact of beach meshing on the White Shark population is unknown. In May 1997 it was nominated that beach meshing is a key threatening process under the Endangered Species Protection Act 1992, however the nomination was unsuccessful.

Drumlines are also used to protect humans from sharks. Drumlines are baited lines anchored to the bottom and has a float and marker buoy at the surface. Drumlines are intended to target dangerous species of shark and reduce the by-catch of non-target species. (DEH 2002)

 

Trade

 

Illegal trade of shark products such as, jaws, teeth and fins, is a threat to the population of White Sharks (ICUN 2006). Direct pressure on Great White Shark populations comes from their being targeted for their teeth, jaws and fins, or when they become a nuisance to fishing operations (Bruce 1992). There has been a substantial increase in value of shark products since the 1980’s. White Shark jaws can be sold for tens of thousands of dollars.

Some countries have outlawed the practice of shark finning, however there is no global shark finning regulation.

 

Tourism

 

Tourism is an indirect threat to the White Shark species. Cage diving and shark boat tours attract sharks to an area by berleying (a mixture of fish oil and animal products). The use of berley may encourage White Sharks to appear or stay longer in a location that they would not normally visit (Klimley 1994), and there is the possibility that sharks will become habituated and begin to associate humans and boats with food. The affects on sharks and other marine species from the use of berleying is unknown. However, cage diving and shark boat tours can be beneficial to white shark research. Tagging without capture can be undertaken as well as other important data collection through observations.

 

Tag and Release

 

White shark tagging is an important way of gathering information on the sharks and their movements. As such tagging operations are undertaken in Australia, South Africa and the United Stated of America, with some smaller operations occurring elsewhere. The data gathered helps people understand the movements of the sharks as well as site fidelity, growth, population estimates and mortality estimates . Several different types are used for a complete summary visit the CSIROs website at

http://www.cmar.csiro.au/research/sharks/whitesharks/tags.html

 

Shark attack statistics

 

The White Shark has a reputation as a threat to humans entering the ocean; this reputation is not supported by statistics. As at January 2006 there have been 193 fatal shark attacks in Australian waters (NSW 72, QLD 72, VIC 7, SA 21, WA 13, NT 3, TAS 5) (It must be considered these recordings are all shark species not just the White Shark) (ASAF 2006).

White Sharks are inquisitive creatures, there are consistent reports of encounters where the shark has nudged or bitten divers, surfboards and marine vessels. Sharks use their jaws and snout to investigate strange objects as unlike humans they do not have hands (Martin NDc). Many have survived White Shark encounters; this may suggest that the White Shark is just investigating what the object is, as predatory attacks are powerful and torpedo-like (Martin NDd). Shark attack is a potential risk for anyone who enters the water but it should be put in perspective, the risk of lightning strike is far greater than death from a White Shark attack (ASAF 2006).

 

References

 

ASAF 2006. Australian Shark Attack File: General Information [online] Available: http://www.zoo.nsw.gov.au/content/view.asp?id=235, Accessed 24th July 2006.

 

Bruce, BD 1992. Preliminary observations on the biology of the white shark, Carcharodon carcharias, in South Australian waters, Australian journal of marine and freshwater research, vol 43, pp. 1-11.

 

Casey, J.G. and H.L. Pratt, Jr. 1985. Distribution of the white shark, Carcharodon carcharias, in the western North Atlantic. So. Cal. Acad. of Sci. Mem. 9; pp. 2-14.

 

DEH 2002, White Shark (Carcharodon carcharias) Recovary plan, Department of Environment and Heritage, Commonwealth of Australia.

 

Dudley SFJ and Gribble NA 1999. Management of shark control programmes, FAO fisheries technical paper, issue 378, No. 2, pp. 819-859.

 

Goldman KJ 1997. Regulation of body temperature in the white shark, Journal of comparative physiology B, vol 167, pp. 423-429.

 

IUCN 2006, ICUN red list of threatened species: Carcharodon carcharias [online] Available: http://www.iucnredlist.org/search/details.php/3855/summ accessed: 24th July 2006.

 

Fergerson IK 1998. Review of the great white shark Carcharodon carcharias, [online] Available: http://www.zoo.net.uk/~z9015043/gws_conserv.html accessed: 24th July 2006

 

FSRF 2004. Fox Shark Research Foundation [online] Available: www.sharkfoundation.com, Accessed 24 July 2006.

 

Klimley, PA 1994. The Predatory behaviour of the white shark, American Scientist, vol. 82, no. 2, pp. 122-134.

 

Krogh M 1994. Spatial, seasonal and biological analysis of sharks caught in the New South Wales protective beach meshing programme, Australian journal of marine and freshwater research, vol. 45 pp. 1087-1106

 

Krogh M and Reid D 1996. Bycatch in the protective shark meshing programme off South-Eastern New South Wales, Australia, Conservation Biology, vol. 77, pp. 219-226.

 

Malcolm H, Bruce BD and Stevens JD 2001. A review of the biology and status of white sharks in Australian waters, CSIRO, Hobart, Tasmania, Australia

 

Martin RA N.D. a, Biology of sharks and rays: Electro-reception [online] Available: http://www.elasmo-research.org/education/white_shark/ampulla Accessed: 24th July 2006

 

Martin RA N.D. b, Biology of sharks and rays: Vision and a carpet of light[online] Available: http://www.elasmo-research.org/education/white_shark/vision.htm Accessed: 24th July 2006

 

Martin RA N.D. c, Biology of sharks and rays: Touch and proprioception [online] Available: http://www.elasmo-research.org/education/white_shark/touch.htm Accessed: 24th July 2006

 

Martin RA N.D. c, Biology of sharks and rays: Categories of shark attacks[online] Available: http://www.elasmo-research.org/education/white_shark/attack_categories.htm Accessed: 24th July 2006

 

Pepperell, JG 1992. Trends in the distribution, species composition and size of sharks caught by gamefish anglers off South-Eastern Australia, 1961-90, Australian journal of marine and freshwater research, Vol 43, pp. 213-225.

 

Reid DD and Krogh M 1992. Assessment of the catches from protective shark meshing off New South Wales beaches between 1950 and 1990, Australian journal of marine and freshwater research, Vol. 43, pp. 283-296.

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