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Taxonomy
Kingdom- Animalia
Phylum - Chordata
Class- Chondrichthyes
Order- Lamniformes
Family- Lamnidae
Genus- Carcharodon
Species- C. carcharias
Ecology
Habitat - The Great White Shark is found in colder,
shallow coastal waters but can also be found in temperate ocean water around the world with some sitings on the Coast of California
(Sharkology). They have been spotted mostly in coastal waters around the United States, Australia, and South Africa.
Food - The Great White start off eating smaller
sharks, sting rays, and other marine animals when they are smaller. As time passes and they grow larger, they then eat things
such as sea lions, smaller whales, and elephant seals (Long). Great whites are often caught during commericial fishing which
is harming their populations further. Without the great white species, certain number of marine animals would sky rocket which
would affect the food chain in general. Also, the Great White doesn't chew it's food, but rather swallows it whole. After
eating a large meal, they can survive without eating again for another month or so(Hughes 2006).
Natural Predators:
Great White's Natural Predators
Even though the Great White is considered one of the greatest predators of the sea, it too must survive the first couple years
of its life in order to make to the top of the food chain. Many "pup" Great Whites don't live past the first year. Some of
their predetors are found within their own species. What's interesting about their species is that after they are born, even
their own mother may see them as prey (Hughes 2006). They are also often preyed upon by sperm whales and orcas (Wikipedia).
Great White as a Natural Predator
A study conducted between 1997 and 2003 by four scientists in South Africa revealed 2088 observed natural predations by white
sharks in the waters near Seal Island, a hotbed for white shark activity. Attacks on cape fur seals were observed and attacks
took place 121 times on seal-shaped decoys from observation vessels. The researchers found that most attacks took place in
under a minute and consisted of a single breach, with predatory success rate decreasing rapidly with increasing duration and
number of subsequent breaches (Collier, 1121). Researchers detected predatory events by one or more of the following: (1)
white shark breach, with or without a seal in its mouth; (2) a sudden change in travel behavior of the seals, (3) a large
splash accompanied by a blood stain, oil slick and distinctive odor, sometimes accompanied by secondary indicators like entrails,
a floating seal head; (4) highly localized circling and/or plunge-diving by gulls and other seabirds. During these observations
every effort to minimize observer effects on the predatory events and the events were classified as successful, in which the
seal was consumed, or unsuccessful, in which the seal escaped (1123). As previously stated, a total of 2088 predatory interactions
between white sharks and Cape fure seals between 1997 and 2003. Most of the predatory activity occured between late May and
late August, with the greatest frequency during mid-June and mid-August. Up to 25 predatory interactions were observed in
a single day. The average attack rate was 5.6 attacks per day. The average success rate was 47.3% (1125). The researchers
determined that white sharks at Seal Island appear to select Cape fur seal class, group size and travel direction, as well
as hunting times and locations to maximize their probability for predatory success. They found that the probability for success
in an attack is greatest for the white shark if the seal is incapacitated at the initial strike. White sharks, they determined
are also capable of spectacular breaches from impressive accelerations. Most of the predations on Cape fur seals at Seal Island
occur within two hours of sunrise. They also found, significantly, that white sharks appear to limit activity (predation)
to within a few hours of sunrise (1129). According to these researchers, the white shark is the largest exant predatory fish,
combining many unusual features including large size, supreme muscle strength and brain power, and coarsely serrated teeth.
The white shark relies on fast strikes and rapid jaw protrusion to increase reach (1133)
Reproduction and Behavior
Great White Sharks
are considered marine predators. Females mature anywhere from 12-18 years versus males who mature at 8-10 years. Female
sharks produce offspring every 2-3 years with a litter consisting of 2-10 pups (Marine Species Conservation 2006). The Great
White isn't considered mature until between 10-12 years of age (Sharkology).
How Great White Sharks Work
Other Facts -The Great White has some very disctinct
characteristics:
-Their teeth are very unique than that of any other shark. They are serrated and act like hundreds of tiny knives when biting
prey.
-Males and females also have different characteristics. The external clasps are located on the underside of only the male.
-The average size and weight is 14-18 feet long and 1,500-4,000 pounds.
-The Great White Shark is not actually white! It's belly is, while the rest of its body is gray or blue. Why? For hunting
purposes.
-The Great White's primary sense is its smell. How strong is that exactly? They can smell one tiny drop of blood in 25
gallons of water.
-Have you ever seen the movie JAWS? Hollywood gives us the wrong impression of Great White attacks. Of the annually reported
attacks (30-50) only 10-15 are actually fatal
.
-Great White's are known to poke their heads out of the surface of the water. This could be to spot potential prey.
-They have up to 3,000 teeth at one time! No wonder they are at the top of the food chain !!
*Above information from Enchanted Learning
Tiger Homes
-Recently, great advancements have been made in scientific research of Great Whites with the advent of
satellite tracking. Scientists were able to track a Great White from South Africa to Australia and back. It was never known
that any fish was able to make this journey and make it as fast as it did. The shark's approximate 12,900 mile swim took only
99 days. It is thought that the shark swam near the surface and used mainly the sun and moon as primary navigation (Roach).
Population Status
The Great White Shark population is believed
to have declined between 60-95% in the past 50 years(Marine Species Conservation 2006). Tagging is the best method of estimating
population size. Tagging has been documented as somewhat successful. However, there is plenty of room for error as tags
can be reported inadequetly, and if the shark is accidentally or purposely captured, the party responsible is less likely
to report the animal since it is an endagered species. Also, tagging can result inthe Jolly-Seber Method: a situation where
shark can be tagged and recaptured more than once. (White Shark Trust for Research and Conservation)
Endangered Status
The Great White is listed as Vulnerable on the IUCN list,
in Appendix II of CITES, and is not currently listed on USFWS.
Reasons for Decline
-trade
-tourism
-tagging and releasing
-shark control activities (i.e. netting,
caging, etc.)
-interaction with fisheries
The great white shark has a trophy status among fishermen and a lucrative business exists to allow these fishermen to catch
a great white. According to WhiteSharkTrust.org a large set of jaws from a great white can net $10,000 or more. Individual
teeth can also net big bucks. A simple search of the web for pictures of great whites often conjures up websites selling great
white teeth that have often been fashioned into jewelery. Cage diving, while not typically harmful to great whites, also constitutes
part of the problem (Fergusson, 1998). Often these cage dives are major tourist draws, especially for thrill seekers, however,
they are often conducted by the very big game fishermen hunting great whites for its trophy status. The status of the great
white as a man eater also seems to drive these individuals to seek out this vulnerable species. Following the release of JAWS
in 1975 the great white has reached cult status and measures, often extreme and unnecessary, were taken to ensure ocean swimmer's
safety (whitesharktrust.org). Ian K. Fergusson, in his review of the great white, notes that the flesh often sells for high
prices in seafood restaurants. The depletion of the great white's prey also effects the shark's suvival rate, fortunately
the white shark is rather adaptable (Fergusson, 1998).
Protection Measures Implemented
The White Shark Recovery
Plan was implemented in 2002 by Australia (Marine Species Conservation 2006). Also, a genetic test of captured species during
commericial fishing was recently by Damien Chapman and colleagues. Their test was specifically designed to decipher great
white shark parts from others that were being collected during commerical fishing. This successful testing will greatly reduce
the number of great white parts that are being used and sold all over the world.
Based on the results of a research tagging
program, conservation efforts should be developed and implemented in other regions and all over the world's oceans (wcs.org
2003).
Prognosis for Recovery
The White Shark Recovery Program shows the plan of action they want to take on recovering this species. Some of their main plans include
but are not limited to:
*monitoring commercial fishing
*developing research programs
*promote awareness of the decreased number
*reduce the amount of trade
Distribution
Great White Sharks are located most frequently off the coast of Southern Australia, South Africa, Northern
California and the North Eastern United States(Marine Species Conservation 2006). However, they have also been reported off
the Gulf coast, Hawaii, South America, New Zealand, Scandinavia, Japan, Eastern China and in Southern Russian. Below is a
map that shows the coastlines that the great white has been spotted. (Click on map for original website)
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