SHARK

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).

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, can be 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 treated with caution.

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 and dentition, it should always be treated with caution.

SHORTFIN MAKO SHARK  

Isurus oxyrinchus

WHAT TO LOOK FOR: A streamlined shark with a conical snout, long caudal keel and large crescentic caudal fin. 

COLOR: Metallic blue to dark gray above; white below

SIZE: Males mature when they are about 6.2 ft [1.9 m] in length, and they will grow to at least 9.3 ft [2.84 m] in length. Females mature when they are about 9.1 ft [2.8 m] in length, and will grow to a length of 12.9 ft [3.94 m], possibly longer.

TEETH: Large awl-shaped non-serrated grasping teeth.

HABITAT: Offshore littoral and epipelagic species found in water warmer than 60ºF [16ºC], from surface to at least 500 ft [152 m].

DISTRIBUTION: Circumglobal in temperate and tropical seas .

BIOLOGY: Prey - Fish (including fast-swimming species such as tuna, bonito and swordfish), squid and smaller sharks.  Reproduction - Ovoviviparous. Embryos are ovophagous; smaller siblings are consumed by larger siblings. Litters range from 4 to 6 pups, and size at birth is 1.9 to 2.6 ft [60 to 80 cm].

BEHAVIOR: The shortfin mako shark, like the white shark, is warm-bodied. This is an extremely active shark. It is the fastest of all the sharks and famed for its spectacular leaps from the sea.

DISPOSITION: Hyperactive 

Danger to humans - Unprovoked attacks on swimmers have been determined and the sharks attempted to inflict multiple bites. Unprovoked attacks on divers are rare, probably because the shark is usually found well offshore. However, its speed and aggressiveness, particularly around speared fish, indicate that it should be regarded with caution.

LEMON SHARK  

Negaprion brevirostris

WHAT TO LOOK FOR: A big stocky short-nosed yellowish shark. Its dorsal fins are about the same size.

COLOR: Dark brown, olive or pale yellowish-brown above; yellowish below.

SIZE: Males mature at about 7.3 ft [2.24 m] and reach at least 9.15 ft [2.79 m]. Females mature around 7.8 ft [2.39 m] and reach at least 9.3 ft [2.85 m].

TEETH: Teeth in upper jaw have narrow triangular smooth-edged cusps and broad finely-serrated bases. Lower jaw teeth have narrow erect smooth-edged cusps.

HABITAT: Inshore species that may enter fresh water.

DISTRIBUTION: Western Atlantic from New Jersey to southern Brazil, including the Gulf of Mexico and Caribbean Sea. Eastern North Atlantic including Senegal and Ivory Coast. Eastern Pacific from southern Baja to Equador.

BIOLOGY: Prey - Bony fishes, rays, small sharks, crustaceans, molluscs and sea birds.
Reproduction - Viviparous with a yolk-sac placenta. Gestation is about 12 months. Litters range from 4 to 19 pups, and size at birth is 23.6 to 25.6 inches [60 to 65 cm].

BEHAVIOR: The shark is nocturnal; it is active at night close inshore: around docks, saltwater creeks, estuaries, bays and inlets.

DISPOSITION: Danger to humans - This species has been involved in unprovoked incidents in South Carolina, Florida and Texas. It may become very aggressive toward divers if molested.

OCEANIC WHITETIP SHARK  

Carcharhinus longimanus

WHAT TO LOOK FOR : A large shark with large rounded white-tipped fins. The shark has a high rounded first dorsal fin and very long paddle-shaped pectoral fins

COLOR: Gray bronze above, white below. White mottling on dorsal and pectoral fins.

SIZE: Most specimens are 6.5 ft [2 m] or less, but a few individuals may reach a total length of 11.5 to 12.9 ft [3.5 to 3.95 m]. Males mature at 5.7 to 6.5 ft [1.75 to 1.98 m] and reach at least 8 ft [2.45 m]. Females mature at 5.9 to 6.6 ft [1.8 to 2 m], and reach at least 8.8 ft [2.7 m].

TEETH: Teeth of the upper jaw are broad, triangular and serrated, lower jaw teeth are erect with serrated cusps.

HABITAT: Oceanic, epipelagic, but occasionally coastal. This species is usually found far offshore in the open sea, but it is sometimes found off oceanic islands where the water is 120 ft [37 m] deep. The shark is regularly found in waters 64°F to 82°F [18°C to 28°C], but prefers sea temperatures above 68°F [20°C].

DISTRIBUTION: Circumglobal in tropical and warm temperate seas. Once abundant in the Gulf of Mexico, the species has virtually disappeared due to overfishing.

BIOLOGY:  Prey - Primarily bony fish such as tuna, marlin, jacks, barracuda and dolphinfish, but it also feeds on cephalopods, sea birds, turtles, marine mammals, carrion and garbage. Reproduction - Viviparous, with a yolk-sac placenta. Litter size ranges from 1 to 15. Gestation is about 12 months. Size at birth ranges from 1.9 to 2.13 ft [60 to 65 cm]

BEHAVIOR: The shark cruises leisurely near the surface with its huge pectoral fins outspread. It can be extremely fast and aggressive when competing for food.

DISPOSITION: The oceanic whitetip shark is often very bold and persistent when it is inspecting a potential food source.  Danger to humans - The shark has been implicated in a number of unprovoked attacks on swimmers. Divers report that it is very persistent in baited and unbaited situations. When fended off, an oceanic whitetip shark often returns, circles and approaches again. Its opportunistic feeding habits, heavy build, strong jaws and teeth, and its stubborn aggressiveness indicate that it should be treated with caution.

BLUE SHARK  

Prionace glauca

WHAT TO LOOK FOR: A blue-colored shark with a long snout and very long pectoral fins.

COLOR: Indigo blue to bright blue above; white below.

SIZE: Maximum recorded length is 12.5 ft [3.83 m], but there are unconfirmed reports of 15.7 and 21 ft [4.8 and 6.5 m] individuals. Males mature at 5.8 to 9.2 ft [1.82 to 2.81 m] and reach at least 10.2 ft [3.11 m]. Females of 7.25 ft [2.21 m] are sexually mature and reach a length of at least 10.6 ft [3.23 m].

TEETH: Teeth of the upper jaw are serrated and slightly curved, lower jaw teeth have narrower cusps.

HABITAT: The shark is generally found in 44.6º to 60.8ºF [7º to 16ºC] seas, but it can tolerate water as warm as 77ºF [25º]. The shark is usually found close to the surface in areas where the depth exceeds 600 ft [182 m].

DISTRIBUTION: Circumglobal in temperate and tropical seas.

BIOLOGY: Prey - Small schooling fishes and squid, but this species - like other pelagic sharks - is an opportunistic feeder and will feed on smaller sharks, invertebrates, sea birds and carrion. Reproduction - Viviparous with a yolk-sac placenta. Gestation is from 9 to 12 months. Litters may be very large and have ranged in size from 3 to 135 pups. At birth pups range in size from 14 to 20 inches [35 to 51 cm]. The skin of adolescent and adult females is three times as thick as the skin of males, presumably as protection from enthusiastic amorous males.

BEHAVIOR: The sharks are usually seen cruising slowly at the surface, their large pectoral fins outspread and the tips of their first dorsal and caudal fins breaking the surface. The sharks may circle prey before rushing in and attacking, and they may become very active when food stimulus is in the water. Blue sharks are found in large aggregations, but not schools, and sexual segregation occurs in parts of their range.

DISPOSITION: In staged “shark feeds” off California the sharks become very active and aggressive. Danger to humans - Thought to be responsible for a number of incidents involving shipwreck victims in World War II.

GALAPAGOS SHARK  

Carcharhinus galapagensis

WHAT TO LOOK FOR: A large fairly slender gray shark with a moderately broad rounded snout. The shark has no conspicuous markings on its fins. This species resembles the dusky shark, but it has a taller dorsal fin and a low interdorsal ridge.

COLOR: Brown gray above, white below. Most fins have dusky tips and the shark has a faint white band on its flank.

SIZE: Males mature at 5.6 to 7.75 ft [1.7 to 2.36 m] and reach a total length of at least 9.5 ft [2.9 m]. Females mature about 7.7 ft [2.35 m], and reach a total length of more than 9.8 ft [3 m]. The maximum size for this shark may be 12.1 ft [3.7 m].

TEETH: Triangular serrated slightly oblique teeth in upper jaw, and narrow erect teeth in lower jaw.

HABITAT: Found inshore and offshore (but not pelagic) near or on continental and insular shelves from the surface to at least 590 ft [180 m].

DISTRIBUTION: Circumtropical

BIOLOGY: Prey - The shark feeds primarily on bottom fishes such as sea bass, flatfish, triggerfish and eels, but it will also feed on flyingfish, octopus, squid, and sometimes consumes garbage. Reproduction - Viviparous, with a yolk-sac placenta. Size at birth ranges from 22 to 32 inches [57 to 80 cm].

BEHAVIOR: The Galapagos shark is aggressive, but it will give way to a silvertip shark, C. albimarginatus. This species is dominant over the blacktip shark, C. limbatus.
Like the gray reef shark C. amblyrhynchos , the Galapagos shark may make a threat display (arched back, raised head, lowered pectoral and caudal fins while swimming in a twisting rolling motion). An attack may follow the threat display.

DISPOSITION: Danger to humans - It has been said that this species was involved in unprovoked fatal attacks on swimmers, but at present GSAF records do not confirm such statements. Divers report that the shark is very inquisitive and attempts to sample divers' swim fins and hands. Aggressive actions taken by divers may startle the shark but it often circles back, bringing more sharks in its wake.

CARIBBEAN REEF SHARK  

Carcharhinus perezi

WHAT TO LOOK FOR: A large shark with a short bluntly-rounded snout, an interdorsal ridge, and no prominent markings on its fins. 

COLOR: Gray brown to olive above, white to yellowish below.

SIZE: Most sharks encountered by divers are about 5.2 ft [1.6 m] in length. Males mature when they are between 4.9 and 5.5 ft [1.52 to 1.68 m], females at 6.5 to 9 ft [2 to 2.95 m].

TEETH: Teeth in both jaws are serrated. Teeth of the upper jaw have narrow cusps and broad bases and are semi-erect to oblique, teeth of the lower jaw are narrow and erect with triangular cusps and broad bases.

HABITAT: The shark is a tropical inshore bottom dweller of the continental and insular shelves. It is often found on coral reefs and adjacent to drop offs.

DISTRIBUTION: Western Atlantic from Florida to southern Brazil, Bahamas, Gulf of Mexico and the Caribbean Sea. It is the commonest shark on coral reefs in the Caribbean.

BIOLOGY: Prey - Thought to feed on fishes and rays.  Reproduction - Viviparous. Litters of 4 to 6 pups have been reported. Size at birth is 24 to 30 inches [60 to 75 cm].

BEHAVIOR: This species has been observed in caves and lying motionless on the bottom.

DISPOSITION: In staged “shark feeds” in the Bahamas the shark may make close passes at divers. It is rarely aggressive, but four incidents have been recorded.

DUSKY SHARK  

Carcharhinus obscurus

WHAT TO LOOK FOR: A large gray shark with a short broadly rounded snout, no markings on its fins, and it has an interdorsal ridge. 

COLOR: Gray to bluish gray above, white below

SIZE: Males mature at about 9.1 ft [2.8 m], and reach at least 11.15 ft [3.4 m]. Females mature betwen 8.4 and 9.8 ft [2.57 and 3 m] and reach at least 11.9 ft [3.65 m].

TEETH: Broad serrated teeth in upper jaw, narrow serrated teeth in lower jaw.

HABITAT: The shark is found on continental and insular shelves and oceanic water adjacent to them. It ranges from the surf zone to far out to sea, and from the surface down to 1312 ft [400 m].

DISTRIBUTION: Cosmopolitan in warm temperate and tropical seas.

BIOLOGY:  Prey - Small sharks feed on bottom dwelling animals. Large specimens feed on a variety of reef and pelagic fish including sardines, tunas, eels, lizardfishes and flatfishes, smaller sharks, rays, skates, squid, octopus, cuttlefish, crabs, lobsters, starfish, barnacles, bryzoans and even whale meat and garbage.  Reproduction - Viviparous, with a yolk-sac placenta. Litters usually consist of 3 to 4 pups. Size at birth is 27 to 39 inches [69 to 100 cm].

BEHAVIOR: The shark is migratory in temperate and subtropical areas of the northern Pacific and western north Atlantic, moving south in winter and north in summer. Young sharks form feeding aggregations.

DISPOSITION: Danger to humans - Because of its size and dentition the shark is considered potentially dangerous, and it has been implicated in a number of GSAF cases. In Australia, both the dusky shark and the copper shark are referred to as bronze whalers.

BLACKTIP SHARK  

Carcharhinus limbatus

WHAT TO LOOK FOR: All fins except anal fins are black tipped, and the shark has an interdorsal ridge.

COLOR: Dark gray, blue gray or dusky bronze above, white below. Dorsal fins, pectoral fins, and lower lobe of caudal fin have black tips. A pale band extends along its flank from the region of its pectoral fin to its pelvic fin.

SIZE: Males mature at 5.9 ft [1.8 m], females mature at 6 ft [1.83 m]. The largest shark caught was an 8.1 ft [2.47 m] female.

TEETH: Erect symmetrical teeth with finely serrated edges in both jaws. Teeth of the upper jaw are broad with narrow cusps, and teeth of the lower jaw are narrow.

HABITAT: This is an inshore shark found in shallow coastal waters; it often encountered in estuaries and river mouths.

DISTRIBUTION: Widespread in tropical and subtropical continental seas.

BIOLOGY:  Prey - The shark feeds on schooling fish, small sharks, rays, squid and cuttlefish. Reproduction -Viviparous, with a yolk-sac placenta. Litter size ranges from 4 to 10 pups. Size at birth is 13 to 26 inches [35 to 65 cm].

BEHAVIOR: This is an active shark and is often seen spinning and leaping above the surface. The shark migrates to deeper water in winter. In contests for food this species gives way to Galapagos sharks, C. galapagensis , and silvertip sharks, C. Albimarginatus

DISPOSITION: Small active sharks may approach divers and circle at a distance, but will rarely approach in unbaited situations. Large sharks are usually indifferent to divers once they descend and rarely approach closer than 50 ft [15m]. Nevertheless, this shark can be belligerant with divers when contesting speared fish; spearfishermen frequently refer to blacktip sharks as “sea jackels.” When several blacktip sharks are together they may become hyperactive, particularly in baited situations.  Danger to humans - This species has been implicated in numerous non-fatal incidents.

SILKY SHARK  

Carcharhinus falciformis

WHAT TO LOOK FOR: A large slim oceanic shark with a moderately long rounded snout and an interdorsal ridge. 

COLOR: Dark brown to bronze above, white below. The shark has dusky fin tips and a faint white band on its flank.

SIZE: Males mature when they are about 6 or 7 years of age and attain a length of 6.1 to 7.1 ft [1.87 to 2.18 m] and may reach a length of 9.8 ft [3 m]. Females mature when they are between 7 and 9 years of age and have attained a length of 7 to 7.5 ft [2.13 to 2.3 m], and they may reach a length of at least 10 ft [3.05 m]. The maximum size for this species is 10.8 ft [3.3 m].

TEETH: The teeth of the upper jaw are serrated and have oblique to erect cusps, and the lower jaw teeth are erect.

HABITAT: The shark is found near edges of continental and insular shelves as well as the open sea. The shark has been found at a depth of 1,640 ft [500 m], but it also occurs inshore at the surface and in areas where the water is only 18 inches [45 cm] deep. The shark, abundant offshore and inshore, is oceanic, epipelagic and littoral. This species prefers sea temperatures from 73.5º to 75ºF [23º to 24ºC].

DISTRIBUTION: Circumtropical.

BIOLOGY: Prey - Pelagic and inshore bony fishes including tuna, albacore mullet and porcupine fish, as well as squid and crabs.  Reproduction - Viviviparous, with a yolk-sac placenta. Litters consist of 2 to 14 pups. Size at birth is 27.5 to 34.25 inches [70 to 87 cm].

BEHAVIOR: This is an active, fast and aggressive shark. It is frequently found with schools of tuna. The shark will give way to an oceanic whitetip shark, C. longimanus .

DISPOSITION: The shark usually ignores divers but make may a threat display when approached by divers, however, it has been implicated in several incidents.

GRAY REEF SHARK  

Carcharhinus amblyrhynchos

WHAT TO LOOK FOR: A medium-sized to large shark with a moderately long, broadly rounded snout and a black-edged caudal fin. 

COLOR: Gray dorsal surface and a broad black band on the posterior margin of the caudal fin.

SIZE: Males mature at 4.25 to 4.75 ft [1.3 to 1.45 m], females mature at 4 to 4.5 ft [1.22 to 1.37 m]. Maximum size is 8.3 ft [2.55 m].

TEETH: The teeth of the upper jaw are narrow-cusped and serrated, those of the lower jaw are awl-shaped.

HABITAT: A coastal-pelagic and inshore species common on coral reefs, often in deeper areas near drop-offs to the open sea, and in shallow lagoons adjacent to areas of strong currents. It is often seen cruising near the bottom but will visit the surface, particularly to investigate food sources. Frequently found on leeward sides of small coral islands.

DISTRIBUTION: Indian Ocean, and Western Pacific eastward to Hawaiian Islands.

BIOLOGY:  Prey - Feeds on reef fish less than 12 inches [30 cm] in length, as well as squid, octopus, crabs, lobsters and shrimp.  Reproduction - Viviparous, with yolk-sac placenta. Litter size ranges from 1 to 6 pups following a 12 month gestation period. Size at birth is 18 to 24 inches [45 to 60 cm]. Individuals mature between 7 and 7.5 years, and life-span is thought to be at least 25 years or more.

BEHAVIOR: This is an active, strong-swimming social species that forms daytime aggregations in reef passes and lagoons; at night the groups disperse. Groups of juveniles remain together on pupping grounds.

DISPOSITION: Gray reef sharks are inquisitive, and in seldom-frequented areas divers have been approached very closely by several of these sharks, particularly when they initially enter the water. However, once the sharks' curiosity is satisfied they usually retreat and remain at a distance. Feeding - When feeding stimuli are present the shark may be aggressive and dangerous.

WHAT TO WATCH OUT FOR: This species will perform a threat-display when approached too closely or startled by unusual sounds or quick movements. The display consists of an exaggerated swimming pattern in which the shark wags its head and tail in broad sweeps, arches its back, lifts its head, depresses its pectoral fins and sometimes swims in a horizontal spiral or figure-8 loop in front of its perceived aggressor. The threat may terminate in a high-speed attack.

GREAT HAMMERHEAD SHARK  

Sphyrna mokarran

WHAT TO LOOK FOR: Hammer-shaped head with a nearly straight anterior margin. The first dorsal fin is very tall and falcate. 

COLOR: Dark olive green to brownish gray above, white below. Ventral tips of pectoral fins are not marked.

SIZE: This is the largest of the hammerhead sharks. The shark grows to a length of at least 18.3 feet [5.6 m], and may attain a length of more than 20 feet [6.1 m], however, most individuals encountered by divers are between 10 and 14 feet in length [3 to 4.3 m]. Females mature at a length of 8.2 to 9.8 ft [2.5 to 3 m]; males mature at a length of 7.7 to 8.8 ft [2.3 to 2.7 m].

TEETH: Strongly serrate.

HABITAT: Coastal-pelagic and semi-oceanic shark occurring close inshore and well offshore. Found over the continental shelves, island terraces and in passes and lagoons of coral atolls, as well as over deep water near land. It is found near the surface and from depths of 3 ft to more than 262 ft [1 to 80 m]. It often favors continental and insular coral reefs.

DISTRIBUTION: Circumtropical

BIOLOGY:  Prey - The great hammerhead shark feeds on a wide variety of prey, but favors stingrays, groupers and sea catfishes. It also feeds on squid, crabs, tarpon, sardines, toadfishes, porgies, grunts, jacks, herring, grouper, boxfish, other sharks, skates, guitarfish, cownose and eagle rays . Reproduction - Viviparous, with a yolk-sac placenta. Litters range from 13 to 42 (average 20-40) following a gestation of at least 7 months. Size at birth is 20 to 28 inches [50 to 70 cm].

BEHAVIOR: General - A solitary, nomadic and migratory species. Some populations move poleward during the winter.  Feeding - The shark feeds mostly at dusk. A shark was seen to use the underside of its hammer-shaped head to bludgeon and pin a stingray to the seabed, then the shark pivoted and bit a chunk out of the ray's pectoral fin.  Mating - Mating great hammerheads were reportedly witnessed in 70 ft [21 m] in the Bahamas. The sharks ascended, spiraling slowly around each other and copulated at the surface. While synchronous swimming as a prelude to mating has been observed with other species of sharks, copulation at the surface has not. Most species are though to mate at or near the seafloor.

DISPOSITION: The species is thought to be dangerous, though relatively few incidents have been attributed to it or any other species of hammerhead sharks. The shark has approached divers without displaying aggression. However, due to its size and broad food spectrum the shark should be treated with caution.  Danger to humans - Divers have observed this shark in unbaited situations and found it to be unaggressive.. Due to its large size it is considered potentially dangerous.

BLACKTIP REEF SHARK  

Carcharhinus melanopterus

WHAT TO LOOK FOR: A moderate-sized stocky brownish gray shark with a short, bluntly rounded snout; black and white on tips of first dorsal fin and lower caudal fin lobe. 

OLOR: Light brown or bronze above, white below. First dorsal fin and ventral caudal lobe have a conspicuous black blotch, brilliantly highlighted with white. Other fins have black fin tips. Conspicuous white band on flank.

SIZE: Most adults are less than 5.25 ft [1.6 m] total length. Males mature at 3 to 3.25 ft [91 to 100 cm] and attain a length of 5.9 ft [1.8 m]. Females mature between 3.15 and 3.7 ft [96 and 112 cm], and may reach a length of 4.3 ft [1.3 m].

TEETH: Teeth of the upper jaw are narrow and erect with coarse serrations and cusplets, lower jaw teeth are erect to oblique with narrow serrated cusps.

HABITAT: This is the most commonly encountered shark in the tropical Indo-Pacific

DISTRIBUTION: Western Pacific and Indian Ocean.

BIOLOGY: Prey - Small fish and invertebrates: mullets, groupers, jacks, mojarras, slipjaws, wrasses, surgeonfish, cuttlefish, squid, octopus, shrimp.  Reproduction - Viviparous, with a yolk sac placenta. Litter size ranges from 2 to 4 (usually 4) and pups are 13 to 20 inches [33 to 52 cm] at birth. Pups are born from late winter to early summer following a gestation of (possibly) 16 months.

BEHAVIOR: On flood tide swarms of blacktip reef sharks move over shallow reef flats. They are often seen swimming in calf-deep water with the tips of their dorsal fins breaking the surface.

DISPOSITION: The blacktip reef shark is often quite inquisitive when divers enter the water, but it can usually be driven off. It frequently becomes aggressive around speared fish, and this may be exacerbated by the presence of competing sharks. In these scenarios blacktip reef sharks will rush in to take wounded fish or baits, although in such situations they generally tend to be less aggressive than C. amblyrhynchos.  Danger to humans - This species is responsible for non-fatal incidents involving spearfishermen, surfers, swimmers and waders. Most bites have been on limbs of people wading in shallow water on coral reefs.

BROADNOSE SEVENGILL SHARK  

Notorynchus cepedianus

WHAT TO LOOK FOR: A stout broad-headed, small-eyed shark with seven gill slits and a single dorsal fin situated far back on its body.

COLOR: Pale gray above; white below. Small black spots on body.

SIZE: Maximum size for this species is thought to be 9.5 ft [2.9 m], possibly more. Males mature at 4.8 to 5.9 ft [1.5 to 1.8 m] and reach a length of 7.4 ft [2.26 m] or more. Females mature at 6.3 to 6.8 ft [1.92 to 2.08 m] and reach a length of at least 9.45 ft [2.88 m].

TEETH: Teeth of the upper jaw are blunt and pointed; teeth of the lower jaw are large broad and saw-like with 5 or 6 distal cusplets.

HABITAT : Marine, benthic, neritic on continental shelves from the surface to 150 ft [46 m]. This is a coastal species commonly found in shallow bays.

DISTRIBUTION: Temperate seas.

BIOLOGY: Prey - Bony fishes, rays and other sharks  Reproduction - Ovoviviparous. Litters may contain up to 82 pups. Size at birth is 18 to 21 inches [45 to 53 cm].

BEHAVIOR: This is an active, strong shark. It moves inshore at high tide, and retreats off shore at low tide. Most specimens are seen cruising near the bottom, but they may also be found at the surface. Juveniles are frequently found in shallow water close to shore.

DISPOSITION: Danger to humans - Unknown. The shark is aggressive when provoked. In Australian and New Zealand waters this shark is regarded as dangerous.

BLUNTNOSE SIXGILL SHARK  

Hexanchus griseus

WHAT TO LOOK FOR: A stout shark with six gill slits. The shark has a short blunt snout and its single dorsal fin is set far back near the caudal fin. 

COLOR: Brown to dark gray above; off white below. Its fins have thin white trailing edges.

SIZE: Maximum total length is 15.8 ft [4.82 m]. Females mature at 14.7 to 15.7 ft [4.5 to 4.8 m].

TEETH: Fang-like teeth in upper jaw, broad saw-like teeth in lower jaw.

HABITAT: Marine or benthic and pelagic. The shark is found on continental and insular shelves and upper slopes, from the surface to 6,150 ft [1875 m]. Juveniles are often found close inshore.

DISTRIBUTION: Temperate and tropical seas.

BIOLOGY: Prey - Fish, small sharks and cephalopods.  Reproduction - Ovoviviparous. Litters are large and range in size from 22 to 108. Size at birth is 25.6 to 27.6 inches [65 to 70 cm].

BEHAVIOR: The shark is sluggish, but it is a strong swimmer. Apparently it is nocturnal and very sensitive to high light levels.

DISPOSITION : Unknown. Danger to humans - Due to the shark's large size and dentition it should be treated with caution.

NURSE SHARK  

Ginglymostoma cirratum

WHAT TO LOOK FOR: A large-headed shark with nasal barbels and dorsal fins about the same size.

COLOR: Gray-brown, yellow brown or brown body. Juveniles may have dark spots.

SIZE: Most individuals encountered by divers are less than 10 ft [3 m] total length. Males take about 10 to 15 years to mature, and reach maturity when they are about 8.2 ft [2.5 m] in length and will grow to at least 8.4 ft [2.57 m]. Females take 15 to 20 years to mature, and reach maturity when they are about 7.5 to 7.8 ft [2.3 to 2.4 m] and will grow over 8.5 ft [2.59 m] in length. Maximum length is said to be 14 ft [4.3 m] but most are less than 9.8 ft [3 m].

TEETH: Teeth are similar in both jaws: a single large cusp, flanked on each side by 2 smaller cusps.

HABITAT: Inshore from intertidal to depths of 165 ft [ 50 m] on rock and coral reefs, in channels in mangrove keys and reef flats.

DISTRIBUTION: Western Atlantic from southern Brazil to Cape Hatteras with strays to Rhode Island, including Gulf of Mexico and the Caribbean Sea. Eastern Atlantic in Cape Verde Islands and along the coast of west Africa. Eastern Pacific from southern Baja to Peru.

BIOLOGY:  Prey - small fish and invertebrates: lobster, shrimps, crabs, squid, sea urchins, octopus, snails and bivalves.  Reproduction - Ovoviviparous. Litters range from 21 to 30. Size at birth is 8.25 to 11.8 inches [27 to 30 cm].

BEHAVIOR: The shark is nocturnal; it is an active strong swimmer at night, but is sluggish by day. The shark uses its muscular pectoral fins to clamber over the bottom, but divers usually see the shark lying motionless on the bottom, often with its head in a crevice. By day, nurse sharks may rest in aggregates of 2 to more than 30 individuals, leaning against or atop one another. The shark has a well-defined fixed home range and it may return to the same daytime resting site for long periods of time.

DISPOSITION : Placid and usually indifferent to divers. Danger to humans - Nurse sharks have retaliated when provoked by divers or swimmers.

SAND TIGER 

Carcharias taurus 

(also known as the raggedtooth shark (Africa) and the grey nurse shark (Australia)

WHAT TO LOOK FOR: A stocky shark with protruding snaggle teeth. The shark has a pronounced hump to its back and both dorsal fins are about the same size.

COLOR: Bronze to gray above, white below. May have brown blotches on its body.

SIZE: Maximum size is 10.4 ft [3.18 m]. Adult males range from 7.2 to 8.4 ft [2.2 to 2.57 m]. Females range from 7.2 to 9.8 ft [2.2 to 3.0 m].

TEETH: Large slender awl-shaped smooth-edged teeth with lateral cusplets.

HABITAT: Inshore from surf zone, shallow bays, rock and coral reefs, to at least 630 ft [190 m].

DISTRIBUTION : Warm and temperate waters throughout the world.

BIOLOGY: General - The shark will gulp air at the surface, presumably to achieve neutral buoyancy.  Prey - Primarily a fish eater, but it also feeds on crustaceans and squid.  Reproduction - Ovoviviparous. Embryos are ovophagous; smaller siblings are consumed and only one pup is born from each uterus. Size at birth is 3 to 3.4 ft [95 to 105 cm].

BEHAVIOR: The shark often swims with its mouth ajar and its teeth visible. Divers usually see the shark close to the bottom, cruising 4 to 6 ft [1.2 to 1.8 m] above the sea floor, or hovering almost motionless in cuts in the reef or out on the sand where the current is strongest. Sexual segregation occurs with this species. The shark comes into the shallows at night to feed. This species is migratory, moving to deeper water in winter.

DISPOSITION : The shark is generally placid, despite its ferocious appearance. If approached too closely by a diver the shark will thump its tail with force, creating a loud booming sound that will make the diver's ears ring.  Danger to humans - In the cooler waters of this shark's range, it has - on rare occasions - bitten people. In most cases, the sharks were agitated by spearfishing activities, attempted to steal a spearfisherman's catch and (apparently) inadvertently nipped the diver, or simply blundered into a diver in low visibility.

  

SPOTTED WOBBEGONG   

Orectolobus maculatus

WHAT TO LOOK FOR: A squat-bodied shark with a large flattened head and fleshy beard. 

COLOR: A well-camouflaged shark. It is pale with a meshwork of darker narrow lines and spots.

SIZE: About 4 ft [1.2 m].

TEETH: Enlarged very sharp fang-like teeth.

HABITAT: Tropical inshore reefs and tidepools.

DISTRIBUTION: Western Pacific, including New Guinea and northern Australia.

BIOLOGY:  Prey - Bottom fish and invertebrates  Reproduction - Ovoviviparous.

BEHAVIOR: General - The shark is nocturnal; it rests on the bottom by day and prowls the reef at night, clambering about using its paired fins.

DISPOSITION: Usually unaggressive unless provoked.  Danger to humans - Divers have approached and photographed the shark by day without inciting aggression, but it has bitten waders and fishermen in tidepools. Treat with caution because of its formidable dentition.

BASKING SHARK 

Cetorhinus maximus 

WHAT TO LOOK FOR: A very large shark with a pointed snout, huge mouth and gill slits that almost encircle the head, strong lateral keels on caudal peduncle, and a lunate tail.

COLOR: Variable. Darker above than below, often with a mottled pattern on back and sides with white blotches under the head.

SIZE: Males mature at less than 18 ft. [5.7 m], females at 26 ft. [8 m], maximum size 33 ft.[10 m].

HABITAT: Coast to edge of the continental shelf.

DISTRIBUTION: Worldwide in cold to warm temperate seas.

BIOLOGY:  Prey – Plankton. May shed gill rakers but no evidence for hibernation in winter.  Reproduction – One litter of six pups reported, presumably oophagous.

BEHAVIOR: Highly migratory . Often seen feeding on surface aggregations of plankton, moving slowly forward with open mouth. The sharks are sometimes seen in large groups. Complex courtship behavior has been reported. Can leap out of the water.

DISPOSITION: Generally placid but has been known to bump boats.

NOTE: This species is endangered regionally in areas where a targeted fishery existed. The basking shark is listed as vulnerable on the IUCN Red List. It is protected in several countries, and in 2002 it was placed on CITES Appendix II.

SPINNER SHARK 

Carcharhinus brevipinna 

WHAT TO LOOK FOR: A long and slender shark with a very pointed snout. The pectoral, anal and lower caudal fins usually have black tips. Similar in appearance to a blacktip shark (C. limbatus ) which has a somewhat larger first dorsal fin with a falcate trailing edge, and the anal fin of a blacktip shark does not have a black tip.

COLOR: Gray to bronze above, white underside, with a faint white bank on its flank. The second dorsal, anal, and pectoral fins as well as the lower lobe of the caudal fin have black or dark gray tips in large juveniles and adults. The pelvic, first dorsal, and dorsal caudal lobe may also have black tips, but not always. The fins of young sharks are unmarked.

SIZE: Males mature at 5.2 to 6.7 ft [1.59 to 2.03 m], females mature at 5.6 to 6.6 ft [1.7 to 2 m], maximum length of 9.8 ft. [2.78 m], but the average size of these sharks is about 6.4 ft [1.95 m] and 123 pounds [56 kg].

TEETH: This species has a narrow jaw and small narrow-cusped teeth of a fish-eating shark.

HABITAT: Coastal-pelagic on continental and insular shelves, common in shallow coastal waters from the surface to the bottom.

DISTRIBUTION: Warm temperate and tropical Atlantic, Mediterranean and Indo-Pacific.

BIOLOGY:  Prey – Primarily fish, but also feeds on stringrays and cephalopods.
Reproduction – Viviparous (livebearing) with embryos nourished by a yolk-sac placenta. Gestation lasts 12 to 15 months and 3 to 15 pups are born every other year. At birth, pups measure between 24” and 30” [60 to 75 cm] in length.

BEHAVIOR: This is an active, schooling shark. It often makes feeding runs through schools of fish ending in a spinning leap out of the water.

DISPOSITION: Spinner sharks are sometimes attracted to divers who are spearfishing. Although a spinner shark has never been implicated in a fatality, the species has bitten humans. 

BRONZE WHALER SHARK 

Carcharhinus brachyurus ( aka Copper shark) 

WHAT TO LOOK FOR: A large shark with a long moderately rounded broad snout, and a bulge at the base of the upper caudal fin.

COLOR: Olive grey to bronze above, white below, most fins with dusky edges. Its flanks have a pale blaze from below the dorsal fin to the tail.

SIZE: Males mature at 6.6 ft to 7.5 ft [2 to 2.3 m], females mature at 7.9 feet [2.4 m], maximum length about 9.8 ft [3 m] .

TEETH: The upper teeth have a distinct outwardly hooked shape.

HABITAT: Often seen close inshore feeding on schooling fish, frequently within the surf zone. It is also found around offshore islands over deep water and to depths of 100 m.

DISTRIBUTION: Warm temperate to subtropical waters of the Atlantic, Mediterranean and Indo Pacific. It is seasonally migratory in at least part of its range. Along the coast of southern Africa it follows the giant shoals of migrating sardines.

BIOLOGY:  Prey – Feeds on pelagic, shoaling and bottom bony fishes, cephalopods, smaller sharks, and rays.  Reproduction – Viviparous; females nourish embryos with a yolk-sac placenta and give birth to live young.

BEHAVIOR: This is an active fast-moving shark, and it can leap out of the water.

DISPOSITION: This species has been implicated in bites to humans, particularly spearfishermen.