Oceanic Whitetip SharkCarcharhinus longimanus
This large shark is easily recognizable for the white tips to its fins, including the very rounded dorsal fin and long, paddle-like pectoral fins. Solitary and slow-moving, it prefers the upper layers of deep water areas, where it is an opportunistic and competitive hunter. They are considered one of the most dangerous sharks to humans because they take advantage of ship and plane wrecks and are suspected of many unrecorded human fatalities.
English language common names include oceanic whitetip shark, Brown Milbert's sand bar shark, brown shark, nigano shark, shark, whitetip, whitetip shark, white-tip shark, and whitetip whaler. Other common names include apoapo (Samoan), cazón (Spanish), galano (Spanish), galha branca (Portuguese), Hochsee-Weißspitzenhai (German), ikan yu (Malay), köpek baligi (Turkish), marracho (Portuguese), marracho oceánico (Portuguese), marracho-de-pontas-brancas (Portuguese), oceanische witpunthaai (Dutch), opesee-wittiphaai (Afrikaans), parata (Tahitian), pating (Tagalog), rameur (French), requin à aileron blanc (French), requin blanc (French), requin canal (French), squala alalunga (Italian), tiburon oceanico (Spanish), valkopilkkahai (Finnish), weißspitzenhai (German), yeshalifes (Carolinian), yogore (Japanese), and zarlacz bialopletwy (Polish).
Importance to HumansShark fishers utilize longlines set in the open ocean to catch oceanic whitetip sharks. The meat is marketed fresh, frozen, smoked, and dried-salted for human consumption, the skin is used for leather, fins for finsoup, and the liver oil for vitamins. It is also processed into fishmeal. Tuna fishermen dislike the oceanic whitetip shark as it has been known to follow tuna boats and damage or consume catches.
Danger to Humans
Although primarily found offshore, this shark is considered potentially dangerous It is often the first species to be seen in waters surrounding mid-ocean disasters. During both World Wars, the oceanic whitetip shark was of major concern due to the high number of torpedoed boats and shot-down planes. The Nova Scotia steamship was sunk by torpedoes from a German submarine off the coast of South Africa. Close to 1,000 men were on board, however only 192 survived. It is believed that many of the fatalities were victims of the oceanic whitetip shark in what eyewitness accounts described as a "feeding frenzy". In encounters with divers, ocean whitetip sharks have shown little fear and much persistence investigating and circling the ongoing activities. Due to this shark's opportunistic feeding habits and strong jaws as well as its boldness and unpredictability around divers, this shark should be treated with extreme caution. Many potential attacks have been averted by quick action on divers' parts such as bumping the sharks on the snout to avoid close contact.
The oceanic whitetip shark is distributed worldwide and is a common resident of warm open ocean waters. Due to its extreme abundance, this shark is subject to pressure as bycatch in tuna and other oceanic fisheries. Its fins are especially highly prized due to their large size while the remainder of the shark is often discarded. Although little is known regarding current fishing pressure, it is likely to come under increased pressure in the future.
The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Geographical DistributionThe oceanic whitetip shark is distributed worldwide in epipelagic tropical and subtropical waters between 20°North and 20°South latitude. Its range includes Maine, U.S. south to Argentina in the western Atlantic Ocean and from Portugal to the Gulf of Guinea and possibly in the Mediterranean in the eastern Atlantic. In the Indo-Pacific this species is found in the Red Sea and East Africa to Hawaii, Samoa, Tahiti and the Tuamoto Islands and in the eastern Pacific it ranges from southern California, U.S. south to Peru, including the Galapagos. It is considered a highly migratory species by Annex I of the 1982 Convention on the Law of the Sea.
HabitatThis shark is usually observed well offshore in deep water areas (0-500 feet (0-152 m)) although on occasion it has been reported in shallower waters near land, usually near oceanic islands. Longline capture data in the Pacific Ocean shows that abundance of this shark increases along with distance from land. It is one of the top three most abundant oceanic sharks, which also include the blue shark (Prionace glauca) and the silky shark (Carcharhinus falciformis). The oceanic whitetip shark is very abundant throughout its range which includes water with temperatures are above 70°F (21°C). Although this shark is primarily solitary, it has been observed in "feeding frenzies" when a food source is present. It is a slow swimmer with equal amounts of activity during the day and nighttime hours. Reports have described swimming behavior in open waters at or near the surface of the water as moving slowly with the huge pectoral fins spread widely.
Oceanic whitetip sharks are often accompanied by remoras, dolphin fishes, and pilot fishes. An unusual behavior of the oceanic whitetip shark is its association with the shortfin pilot whale (Globicephala macrorhynchus) in Hawaiian waters as reported by Jeremy Stafford-Deitsch (1988). They are often observed swimming along with pods of pilot whales. Although the reason for such behavior is unknown, it is suspected to be food-related. Pilot whales are efficient at locating squid upon which the oceanic whitetip sharks also feed.
1. First dorsal fin is broadly rounded
2. Pectoral fins are long and paddle-shaped
3. First dorsal, pectoral, and caudal fins usually have white mottling on tips in adults
The oceanic whitetip shark is easy to distinguish among species belonging to the family Carcharhinidae. This stocky shark has a large rounded first dorsal fin and very long and wide paddle-like pectoral fins. The head of this shark includes a short and bluntly rounded nose and small circular eyes that have nictitating membranes. The first dorsal fin is very large with a rounded tip, originating just in front of the free rear tips of the pectoral fins. The second dorsal fin originates over or slightly in front of the anal fin origin. Possessing broadly rounded tips, the pectoral fins are very large and elongated.
This species is commonly named the oceanic whitetip shark for the whitish-tipped first dorsal, pectoral, pelvic, and caudal fins. These white markings are sometimes accompanied by white mottling on the fins or black markings in young individuals. There may also be a dark saddle-shaped marking present between the first and second dorsal fins. The body of the oceanic whitetip shark is grayish bronze to brown in color, varying depending upon geographical location. The underside is whitish with a yellow tinge on some individuals.
The upper jaw contains broad, triangular, serrated teeth, while the teeth in the lower jaw are more pointed and are only serrated near the tip. These teeth, located in powerful jaws, are effective at holding and tearing prey. The arrangement of the teeth is 14 or 15 on each side of the symphysis of the upper jaw and 13-15 teeth on either side of the lower jaw symphysis.
The dermal denticles of the oceanic whitetip shark lie almost flat resulting in a smooth to the touch skin. The denticles overlap only slightly with some skin exposed. Usually having 5, but sometimes 6 or 7, ridges, the denticles are broader than long.
Size, Age, and Growth
Oceanic whitetip sharks grow to large sizes, with some individuals reaching 11-13 feet (3.5-4 m). However, most specimens are less than 10 feet (3 m) in length. The maximum recorded weight for this species is 370 pounds (167.4 kg). Males mature at 5.7-6.5 feet (1.7-1.9 m) in length while females mature at slightly longer sizes of 5.9-6.6 feet (1.8-2.0 m), both corresponding to an age of 6 or 7 years. Females reach greater maximum lengths than males. The longest-lived known specimen lived to an age of 22 years.
The oceanic whitetip shark feeds on bony fishes including lancetfish, oarfish, barracuda, jacks, dolphinfish, marlin, tuna, and mackerels. Other prey consists of stingrays, sea turtles, sea birds, gastropods, squid, crustaceans, and mammalian carrion (dead whales and dolphins). Feeding behavior has been reported for this shark and includes biting into schools of bony fishes. It also swims through schools of feeding tuna with wide-open jaws into which the tuna unknowingly swim. The oceanic whitetip shark has also been observed eating garbage that is disposed of at sea. If other species of sharks are encountered by the oceanic whitetip during feeding activities, the oceanic whitetip becomes aggressive and dominates over them.
Records indicate the oceanic whitetip shark mates during the early summer months in the northwestern Atlantic Ocean and the southwestern Indian Ocean. This shark is viviparous in reproduction, meaning the eggs hatch inside the mother with the young being born alive. During the year-long gestation period, the embryos are nourished by a placental yolk-sac that is attached to the uterine wall by umbilical cords. In early summer, a litter ranging from 1-15 pups is born. Litter number is proportional to the size of the mother. Each pup is approximately 24-25.6 inches (60-65 cm) in length upon birth.
Large sharks are potential predators of the oceanic whitetip shark, especially immature individuals.
Cuban naturalist Felipe Poey originally described the oceanic whitetip shark as Squalus longimanus in 1861, followed by a name change to Pterolamiops longimanus and then to the currently valid name of Carcharhinus longimanus. The genus name Carcharhinus is derived from the Greek "karcharos" = sharpen and "rhinos" = nose. The species name longimanus is translated as long fingers for the characteristic long paddle-like pectoral fins. Synonyms used to refer to this species in past scientific literature include Carcharius obtusus Garman 1881, Carcharius insularum Snyder 1904, Pterolamiops magnipinnis Smith 1958, and Pterolamiops budkeri Fourmanoir 1961.
Prepared by: Cathleen Bester