Oceanic Whitetip Shark

The Oceanic Whitetip is a species of very ferocious sharks that are often regarded as the boldest, most inquisitive and opportunistic feeders of all shark species. These creatures live in the deep waters of the open oceans almost throughout the world and are known to be a trickster, often getting away with its crimes without leaving any evidence.

It is not to be confused with the white tip reef shark, which is different from the oceanic whitetip, with the former being much smaller and less aggressive. The oceanic whitetip shark is so named because of the white hues on the tips of their fins.

Physical Description

Size: A healthy, adult individual is between 3 to 3.9 m (9.84 to 12.80 ft) in length.

Weight: A considerably large adult specimen can weigh around 170 kg in an average.

Body:, The body color may vary, depending on their geographic locations, from brown or gray to olive gray, beige or bronze, and occasionally, even bluish. The stomach (ventral) part is usually white, and, at times, with a tinge of yellow.

Fins: The first dorsal fins are rounded. The pectoral, first dorsal, pelvic, and caudal fins are often white or show white mottling.

Eyes: Large, rounded eyes with a nictitating membrane over each.

Teeth: The sharp upper teeth are considerably broad with a triangular shape, and are serrated at the edges; the teeth in the lower jaw are relatively narrow, having broad bases and serrated cusps.

Sexual Dimorphism: There are no visual differences between the sexes, except that the females are larger and somewhat heavier than the males.

Lifespan

The currently estimated longevity of the male oceanic whitetip shark is about 12 years, and of the female is 16 years in the wild.

Distribution

These enormous fish are globally widespread and are found in the waters of all the three major oceans of the world – Indian, Atlantic, and Pacific.

Habitat

These ferocious sharks are usually found far from shore down to a depth of about 500 feet from the water surface, mostly in the warmer waters with temperatures of around 22° C or higher.

Behavior

These are primarily solitary creatures, although they are often seen gathering at a common place where food is lavishly available.  They are natatorial and can cover long distances. These sharks are ready to move from one location to the other only to search for food, or else, during seasonal migration from colder to warmer water.

However, they are relatively slow swimmers because of the wideness of their pectoral fins. They have also been noted to undergo a tonic immobility state when an individual goes into a state of trance and remains still.

Interestingly, this has also been done by scuba divers by placing a hand atop a whitetip’s electroreceptors and then rubbing the snout, which temporarily stunned the shark. Researchers often use this method to calm them down before tagging or measuring a specimen. This process makes it less likely to injure them.

Diet

This shark species would feed on just anything moving, but its primary diet includes fast-moving fishes including barracuda, tuna, white marlin, etc. However, they would also eat turtles, seabirds, squids, and other marine creatures.

Reproduction & Life Cycle

Due to the difficulty of sampling, there is no documented data regarding the mating system of these aquatic creatures. However, they have been known to breed once in two years during early summer, when the mating typically occurs in the southwestern parts of the Indian Ocean, and to the northwest of the Atlantic.

The oceanic whitetip shark is viviparous and reproduces live young via internal fertilization. The embryos inside the mother’s abdomen derive nutrition from the yolk sacs connected to the uterine wall.  Using this means, the mother sharks keep supplying the nutrients to the offspring (embryos) until they mature.

The litter size of the whitetips is 5 to 15. The newborn baby sharks are around 65 to 75 cm (26 to 30 in) in length. However, researchers believe that the size of the litter varies with the female’s size.

The young juveniles belonging to both the sexes attain the age of sexual maturity when the cubs are around 1.8 to 1.9 meters (5.8 feet) in length, i.e., 6-7 years old.

Adaptations

1. The first dorsal fin of this shark is distinctly large; the pectoral fins are paddle-like, quite long and wide as well as rounded like many other shark species, which help them immensely in moving through the waters smoothly despite their great size.
2. The nictitating membrane over the eyes, which is rare among the shark species, protects the eyes from external influences.

Enemies, Threats & Predators

The oceanic whitetip shark is a predator at the top of the pelagic food webs, and do not have any natural predators. However, as mentioned, they are extensively hunted down by humans because of their popularity in the booming shark fin soup industry around the world.

Conservation Status

Even in the recent past, the oceanic whitetip was one of the most common species, but is now in serious danger of extinction, since this fish is commercially important for its fins (for the popular ‘fin soup’ dish), meat, oil, and hide (for leather). Because of their rapidly declining population, the oceanic whitetip sharks have been enlisted as ‘VU’ (Vulnerable) by the IUCN 3.1.

Does the Oceanic Whitetip Shark Attack Humans

Oceanic whitetip shark is an aggressive and opportunistic feeder, attacking almost anything moving, which falls on its way. It will also not hesitate to approach divers, swimmers, surfers, or small boats.

However, the oceanic whitetips are seldom encountered since they inhabit the deep oceanic waters. Nonetheless, this species is known to be one of the few sharks that are known to attack, bite or kill humans.

Experts assert that such incidents are very rare, and, almost certainly, are cases of mistaken identity. Several reports have informed that they are often seen around disasters caused by plane crashes or sinking ships, or else if caught by deep-sea fishermen.

Interesting Facts

• A Bahamas fishing spot preferred by fishermen has turned to a source of frustration for the sports since these sharks have repeatedly been stealing their fish. However, it is still a mystery as to how these creatures come to know exactly when a fisherman has caught a fish.
• Presently, the Gulf of Mexico population has gone down drastically in just four decades, coming down to 99%.
• It is thought that these sharks are so intelligent that they can instantly approach a fishing boat to steal fish by just hearing the decreasing sound of the boat engine, as the skipper gradually slows it down after catching a fish.
• Celebrated and veteran marine explorer Jacques Cousteau had ranked this species as one of the most notorious for its brazenness while evaluating its prey.
• The shark has such a big appetite that they have even been seen gobbling garbage disposed at sea.
• This shark turned out to be a principal enemy during the times of World War II, when the ship Nova Scotia sunk in the ocean and the soldiers ended up jumping into the water as their transport was attacked.
• The pilot fish and the dolphin fish are the two fish species that are seen accompanying the oceanic whitetip sharks.