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The oceanic whitetip shark (Carcharhinus longimanus) is a large pelagic shark of tropical and warm temperate seas. It is named after its oceanic habitat (living in deep waters), and the white tips on its fins. It is a stocky shark, the most notable feature of which is its extremely long, rounded fins.


 


Credit: NOAAThe most distinguishing characteristic of C. longimanus is its long, winglike pectoral fins and dorsal fin. These fins are noticeably larger than expected; they are also conspicuously rounded. The shark's nose is also rounded, and its eyes are circular with nictitating membranes. C. longimanus has a 'typical', although somewhat flattened requiem shark body, often with a mildly humpbacked aspect. It is bronze, brown, bluish, or grey dorsally (the color varies by region), and white ventrally (though it may occasionally have a yellow tint). The teeth of the upper jaw are triangular and serrated, while those in the lower jaw are narrow and somewhat fang-like. Most of the fins on its body (dorsal, pectoral, pelvic, and caudal) have a white tips, from whence the name comes.

The maximum size of the oceanic whitetip shark is 4 metres (13 ft), although usually not more than 3 m (10 ft). Its maximum weight is 170 kilograms (370 pounds). The female is larger than the male (though typically only by 10 centimeters (4 in)) with males about 1.8 m(71 in), and females about 1.9 m (75 in).


Solitary Shark? The whitetip shark typically lives on its own, though some gatherings are notable where food is available. Unlike many animals, it does not operate on a day-and-night basis, but rather swims during both — its swimming style is slow with the pectoral fins widely spread. Despite their decided isolation from others of the same species, they may be observed with pilot fishes, dolphin fishes, and remoras. In 1988 Credit: NOAAJeremy Stafford-Deitsch reported seeing the species accompanied by a shortfin pilot whale.

Not So Picky: C. longimanus feeds mainly on pelagic cephalopods and bony fish. However, its diet is often far more varied and less selective — it is known to eat threadfins, stingrays, sea turtles, sea birds, gastropods, crustaceans, mammalian carrion and even rubbish dumped from ships. The bony fish it feeds on include lancetfish, oarfish, barracuda, jacks, dolphinfish, marlin, tuna, and mackerel. Its method of obtaining food often includes biting into a group of fish, or swimming through schools of tuna with an open mouth. When feeding with other species, it becomes aggressive. Peter Benchley has observed this shark swimming among pilot whales and eating their faeces.

Feeding Frenzy I: Groups are often formed when several nearby individuals converge on a food source, whereupon the fabled "feeding frenzy" may occur. The frenzy seems triggered not by blood in the water per se, or by bloodlust, but by the species being especially high-strung and goal-directed when not slowly plying the open ocean, conserving energy between infrequent food events. C. longimanus is a competitive, opportunistic predator with great incentive to exploit the resource at hand, rather than avoiding trouble in favor of a possibly easier meal in the future.

Followers: There does not seems to be a segregation by sex and size as with some other species. Whitetips will follow schools of tuna or squid, and will follow groups of cetaceans such as dolphins and pilot whales as scavengers of the cetaceans' prey. They follow boats as well, and indeed seem to have a vital following-impulse, developed over countless millennia of baitfish migrations and doglike hope that the followed might drop a piece of whatever he is eating. When whaling was still taking place in warm waters, oceanic whitetips were often responsible for much of the damage to floating carcasses.

 


Mating season is in early summer in the northwest Atlantic Ocean and southwest Indian Ocean, although females captured in the Pacific have been found with embryos year round suggesting a longer mating season in this area. Viviparous (young hatch, live and are fed in utero by a placental sac), with litter size varying from one to 15 young. There is a gestation period of one year. Sexual maturity is reached near a length of 1.75 to 2 m (70 to 80 in) for males and females, respectively, though they are born at a size of about 0.6 m (24 in).


The oceanic whitetip is found worldwide in deep, open water, with a temperature greater than 18° C (64.4° F).It prefers waters between 20 and 28° C (68 and 82.4° F) and tends to withdraw from areas when temperatures fall below this. They were once extremely common and widely-distributed, and a map of their habitat appears as a wide band around the world; however, recent data suggest that their numbers have drastically declined. An analysis of the US pelagic longline logbook data between 1992-2000 (covering the Northwest and Western Central Atlantic) estimated a decline of 70% over that period. As a result it is listed as Critically Endangered in these two areas of the Atlantic.

Shark Fin Soup: It is a commercially important species to the extent that its fins are prized for soup and its meat and oil frequently used and is subject to fishing pressure throughout virtually its whole range - although it more often taken as bycatch than on purpose. It steals fish from lines and snatches bait (although it is wary of baited hooks), and is considered more of a nuisance than a resource. It is used fresh, smoked, dried and salted for human consumption and its hide utilised for leather.

Feeding Frenzy II: The oceanic whitetip poses an extremely minimal threat to bathers or inshore sportsman, but a substantial one for humans caught in the open ocean in conditions in which they might be seen as likely prey. Famed oceanographic researcher Jacques Cousteau described the oceanic whitetip as "the most dangerous of all sharks." Despite the greater notoriety of the great white shark and other sharks who are often found nearer the shore, the oceanic whitetip is probably responsible for more fatal attacks on humans than all other species combined, by preying on those who are shipwrecked or downed from planes in the open ocean through disaster or war.

It is an aggressive but slow-moving fish which dominates feeding frenzies, and has attacked more humans than all other shark species combined — it is a notable danger to survivors of oceanic ship and plane wrecks. Given its abundance and threat it was a serious concern in the World Wars, but studies have shown that its numbers are in steep decline: its large fins are highly-valued as the chief ingredient of shark-fin soup and, in common with other species of shark, it faces mounting pressure from fisheries throughout its range.

 

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 Kingdom: Animalia

 Phylum: Chordata

 Class: Chondrichthyes

 Order: Carcharhiniformes

 Family: Carcharhinidae

 Genus: Carcharhinus

 Species: Longimanus