Sunday, August 7, 2016

Oceanic Whitetip Shark

an oceanic whitetip in the Bahamas

The Oceanic Whitetip Shark
           Carcharhinus longimanus

The oceanic whitetip shark is a majestic shark that inhabits the open oceans of the world. One of their claims to fame is the tragedy of the USS Indianapolis. When the ship was sunk on a top-secret mission, less than of a third of the men survived and many deaths were attributed to oceanic whitetip attacks. However, most of the men died from exposure to the elements rather from shark bites.

The oceanic whitetip is a grey to brown shark, known for their long, wide pectoral fins with mottled white tips. They have wide, rounded dorsal fins that are also white tipped. Oceanic whitetips have blunt, rounded snouts and small eyes.

Kingdom : Animalia
Phylum : Chordata
Subphylum : Vertebrata
Class : Chondrichthyes
Subclass :  Elasmobranchii
Superorder : Selachimorpha
Order : Carcharhiniformes
Family : Carcharhinidae
Genus : Carcharhinus
Species : longimanus

Similar Species and Other Family Members:
One species similar to the oceanic whitetip is the whitetip reef shark - although it is similar in name and coloration only. The whitetip reef shark (Triaenodon obesus) is a much smaller shark that lives on coral reefs and has a slender body with a very short snout. They are typically dark brown in color with bright white tipped dorsal and caudal fins.
Triaenodon obesus

The oceanic whitetip is a viviparous shark, meaning it gives placental live birth, just like humans. They tend to have a small amount of pups, around 5 or so per brood.

Female oceanic whitetips tend to reach about 200 cm (6.5 ft) in length, while males tend to be slightly smaller, reaching around 190 cm (6.2 ft). It is possible that oceanic whitetips could reach up to 350 cm (11.4 ft).

Oceanic whitetips feed mainly on pelagic bony fish, such as tuna and dolphin fish. They also eat cephalopods and have been known to eat marine mammals - normally in the form of carrion.

Teeth & Jaws:
The upper teeth of the oceanic whitetip are broad, triangular, and serrated. The lower teeth are more narrow and pointed. 
Upper tooth

Habitat and Distribution:
Oceanic whitetips are found all over the world in warm temperate and tropical waters. They live almost exclusively in pelagic waters, far off-shore.

Conservation Status:
The oceanic whitetip used to be the most abundant pelagic shark in the world; they are now listed as vulnerable on the IUCN Red List. The sharp decline in their population is due mainly to bycatch in pelagic fishing. They also suffer from heavy overfishing and are prized by shark finners for their large fins.

The Sharks of North America, Jose I. Castro
Sharks of the World, David A. Ebert, Sarah Fowler and Leonard Compagno 
note: none of the images are mine

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