WHITE SHARK Carcharodon carcharias


WHAT TO LOOK FOR: A large shark with a heavy spindle-shaped body, conical snout, caudal keel and lunate caudal fin.

COLOR: Slate brown to black above, white below. There is often a black spot at the pectoral fin axil and undersides of pectoral fins have black markings that vary among individuals.

SIZE : Males begin to mature at 7.8 ft [2.4 m], and may reach 18 ft [5.5 m]. Maximum length is at least 20.9 ft [6.4 m], possibly over 26.25 ft [8 m].

TEETH: Large triangular serrated teeth in both jaws. Teeth of the upper jaw are broad, lower jaw teeth are narrower.

HABITAT: This is a coastal and offshore shark of continental and insular shelves. The shark has been found off oceanic islands, and it also occurs close inshore. It penetrates shallow bays in coastal waters and may even venture into the surf. The shark is frequently found in the vicinity of pinniped colonies and has been caught at a depth of 4,199 ft [1280 m].

DISTRIBUTION: Temperate, subtropical and tropical waters worldwide. In the western Atlantic: Newfoundland to Argentina, including the Bahamas. Eastern Atlantic: France to the Cape of Good Hope, and the Mediterranean Sea. Eastern Pacific: Gulf of Alaska to Chile. Central Pacific: Easter Island, Hawaiian Islands and Marshall Islands. Western Pacific: Siberia to Tasmania. Red Sea and Indian Ocean including South Africa and Mozambique, Madagascar, Mauritius and Seychelles, and Western Australia.

BIOLOGY:
General - This species is able to maintain a body temperature as much as 14.4ºF [8ºC] above the ambient water temperature. By keeping the temperature of muscles and internal organs higher than the surrounding water, the white shark's muscular strength and energy level is greater than that of a cold-bodied shark.
Prey - In general, juveniles feed on fish, while adult sharks feed primarily on marine mammals,
Reproduction - Ovoviviparous

BEHAVIOR: This is the super-predator; it is without question the most formidable of all sharks. The white shark swims stiffly, and is capable of great speed. A shark, implanted with a sonic tag, had an average cruising speed of 3.2 kph. The shark sometimes raises its head above the water (“spy hops”), a behavior frequently observed in the vicinity of seal colonies and in baited situations.

DISPOSITION: The white shark is curious and it learns by experience. However the shark does not have hands and it often uses its teeth to inspect an unfamiliar object.
Danger to humans - Sightings of a white shark does not mean that an attack is inevitable; the shark is often indifferent to divers. However, this species has been implicated in numerous unprovoked attacks on swimmers, surfers and divers. Most bites by white sharks are not fatal, but incidents in which a white shark partially consumed a human have occurred. In baited situations divers are advised to remain inside a shark cage.

NOTE: This species is protected in South African territorial waters. It is also a protected species along the eastern coast of the United States, Malta and Australia. In 2004, the white shark was listed on Appendix II of CITES, and it is listed on Appendix I and II of CMS (Bonn Convention).

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TIGER SHARK Galeocerdo cuvier

WHAT TO LOOK FOR: A large shark with an extremely wide, blunt snout and a caudal keel.


COLOR: Varies from brownish, olive, gray to black above; pale gray, dirty yellow, pale gray or white below. Young sharks have tiger-like vertical dark bars, but as the sharks age the marks fade and they are usually absent in adults.

SIZE: Most individuals encountered by divers range between 11 and 14 ft [3.4 to 4.3 m] in length. Males mature at 7.4 to 9.5 ft [2.26 to 2.9 m], and reach a length of at least 12.1 ft [3.7 m]. Females mature between 8.2 and 11.5 ft [2.5 and 3.5 m] and reach a length of more than 18 ft [5.5 m]. One large female caught in 1957 was 24 ft [7.4 m] and weighed 3,110 lbs [1,414 kg], and there is an unverified report of a 30 ft [9.1 m] individual.

TEETH: The teeth in both jaws are identical: heavy cockscomb-shaped cutting teeth resembling diagonally positioned blades. The coarse serrations of the teeth have fine secondary serrations.

HABITAT: Although the shark occurs off oceanic islands and has been photographed at a depth of 1,007 ft [305 m], it is regarded as a coastal species. The shark tolerates a wide variety of marine habitats and may be found in estuaries, turbid waters at river mouths, around jetties and wharves, coral atolls and lagoons.

DISTRIBUTION: Circumglobal in tropical and warm temperate seas.

BIOLOGY:
Prey - The tiger shark is omnivorous; it may attempt to consume virtually anything that can fit between its jaws. It feeds on bony fish, sharks, rays, marine turtles, marine mammals, sea snakes, sea birds, crustaceans, octopus and squid, jellyfish, carrion and garbage.
Reproduction - Ovoviviparous. Gestation is slightly over a year and the litters are large: 10 to 82 pups. Pups, born at a length of 20 to 30 inches [51 to 76 cm], double in length within the first year, but their rate of growth slows as they mature. Most will reach sexual maturity within 7 to 10 years.

BEHAVIOR: General - The shark is usually solitary, but may be found in small groups of up to 6 individuals. This species is nocturnal; it comes inshore at night to feed and retreats offshore by day but often feeds near the surface on overcast days.
Feeding - When feeding the shark uses its wide blunt snout to advantage; a tiger shark feeding on a large stingray was filmed pushing the ray's body into the sand and between rocks -- apparently to gain leverage in order to bite off a mouthful of flesh.

DISPOSITION: A tiger shark is inquisitive, and it may approach submerged divers and circle slowly at close range. Do not be lulled into a sense of security by its slow swimming movement and apparent lack of aggression; this shark may nonchalantly take a bite while remaining cool and casual. Tiger sharks have also become very aggressive toward spearfishermen and divers attracting the sharks in underwater photo sessions.
Danger to humans - The tiger shark, like its jungle namesake, is dangerous; its toll of victims throughout the world is second only to that of the white shark. It is considered the most dangerous tropical shark, and has been blamed for the majority of attacks in Australia and Hawaii. The shark's large size, inquisitiveness and often aggressive nature, combined with large cutting teeth and indiscriminate feeding habits, dictates that a tiger shark should always be regarded as extremely dangerous.

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BULL SHARK Carcharhinus leucas

WHAT TO LOOK FOR: A stocky heavy-bodied gray shark with a short bluntly-rounded snout.


COLOR: Gray with a faint white band on its flank. The fin tips of young sharks are often dusky. Sometimes a bull shark's back appears grazed, but these areas are actually bald patches caused by fluke infections that result in loss of dermal denticles from the skin.

SIZE: Males mature at 5.1 to 7.4 ft [1.57 to 2.26 m], and reach at least 9.8 ft [2.9 m]. Females mature at 5.9 to 7.5 ft [1.8 to 2.3 m], and reach a length of 10.6 ft [3.24 m].

TEETH: Teeth in the upper jaw are triangular and strongly serrated, those of the lower jaw are slender, pointed and edged with fine serrations.

HABITAT: Usually found close inshore in water less than 100 ft [30m] deep.

DISTRIBUTION: Tropical and subtropical shallow coastal waters worldwide. This species has the ability to penetrate fresh water; it has been caught 2,294 miles [3,691 km] up the Amazon River in Peru, 340 miles [547 km] up the Zambesi River, and Lake Nicaragua has a landlocked population.

BIOLOGY:
Prey - The shark feeds primarily on bony fishes, but it is a versatile and opportunistic feeder and will eat smaller sharks, skates, turtles, birds, mammals, crustaceans and offal and garbage. The shark uses the teeth of its lower jaw to impale prey, then it swings its head from side-to-side using the heavy triangular teeth of its upper jaw to carve a mouthful of tissue from its prey.
Reproduction - Viviparous, with yolk-sac placenta. Litter size ranges from 1 to 13. Size at birth is 22 to 31 inches [56 to 81 cm]. Gestation lasts nearly a year.

BEHAVIOR: General - Divers report that the sharks are rarely seen at the surface; most are observed cruising over the top of the reef, and are frequently hosts to remoras.

DISPOSITION: This is a large, aggressive shark with massive jaws and it moves like a seasoned warrior. The GSAF has several cases in which the rapid ascent of a diver may have `released' an aggressive response (similar to when an intruder flees from a guard dog). In each case, after a single bite on the diver's leg (no tissue was removed by the shark), the shark sped back to the reef. More often, when this shark bites, it resembles a pit bull; it makes multiple bites accompanied by head-shaking to remove tissue, and inflicts injuries that are far more difficult to repair than those caused by a white shark. Perhaps because the shark scavenges on carrion and may make forays into polluted areas, wounds caused by this species have a higher-than-usual rate of infection.
Danger to humans - Due to its size, dentition and aggressiveness, it is regarded as one of the most dangerous tropical sharks .

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