Tigershark Galeocerdo cuvier
Adult tiger sharks are among the largest predators in the sea and one of the largest members of the order Carcharhiniformes. They are characterised by the presence of two dorsal fins, both of which lack spines, an anal fin and 5 gill slits.
The anterior one to three gill slits overlap the pectoral fins. Another characteristic of this order is the presence of a nictating membrane, a protective flap of skin that covers the eyes whilst feeding, acting as a third eyelid.
Possibly the most distinctive feature of the tiger shark are the dark black spots in younger individuals that fuse to vertical bars that run the length of the body as the shark ages. These markings are most noticeable in younger sharks and fade as the shark matures, although remain apparent throughout the life of the shark.
The body colour is grey, tinged with a blue to green hue with an underbelly that ranges from white to light yellow. The tiger shark has a robust head and large eyes. The snout is very blunt giving the shark a wedge shaped head. The mouth is wide with large with long labial furrows and contains triangular, heavily serrated teeth.
The tiger shark is one of the largest species, with one specimen reportedly recorded as being 7m in length. However, more common lengths range from 3.25-4.25 m.
A large shark of 5m can weigh over 1500kg, but more commonly, specimens are found to weigh between 385-635 kg.
At birth the size varies from 51-76 cm. Males reach sexual maturity between 2.26-2.90m whilst females mature between 2.50-3.25m.
Tiger sharks are found in temperate and tropical seas throughout the world, except for the Mediterranean Sea. They are found in the Western Atlantic as far south as Uruguay, and around the Gulf of Mexico, Bahamas and Caribbean.
In the Eastern Atlantic they have been reported as far north as Iceland and the UK, due to the presence of the warm Gulf Stream. They are found from Morocco to the Canary Islands and the West coast of Africa including Senegal.
In the Eastern Atlantic they have been reported as far north as Iceland and the UK, due to the presence of the warm Gulf Stream. They are found from Morocco to the Canary Islands and the West coast of Africa including Senegal.
They are also found in the Indian Ocean from South Africa to the Red Sea, as well as Pakistan, India, Sri Lanka, Maldives and Thailand. Their presence in the Western Pacific ranges from Southern China, Japan, Philippines, Indonesia, Australia and New Zealand. In the Western central Pacific they are found around Palau, Solomon Islands, Marshall Islands, Tahiti, and Hawaii.
They are also present in the Eastern Pacific, including Southern California, Peru and the Galapagos Islands.
This species inhabits coastal and pelagic waters from surface waters to a depth of around 350 m. Tiger sharks can tolerate a wide range of marine habitats but frequent turbid waters close to, or on, the continental shelf and have been reported to be present.
They are also present in the Eastern Pacific, including Southern California, Peru and the Galapagos Islands.
This species inhabits coastal and pelagic waters from surface waters to a depth of around 350 m. Tiger sharks can tolerate a wide range of marine habitats but frequent turbid waters close to, or on, the continental shelf and have been reported to be present.
The tiger shark is the only ovoviviparous requiem shark. The embryo develops within an egg inside the womb and the embryo receives nutrition from the yolk sac and not from the mother. Gestation in this species ranges from 14-16 months, with females giving birth to between 10 to 80 pups.
Mating takes place between March and May the Northern Hemisphere with young being born between April and June the following year. It is believed that they give birth between November and January in the Southern Hemisphere. Due to the large size of the young at birth, many scientists believe that uterine nutrition is enhanced by uterine milk, which is secreted by the lining of the uterus during pregnancy.
Tiger sharks are nocturnal moving into inshore, shallow waters to feed at night then back to deeper water during the daytime. They are voracious feeders with reports stating that they will eat anything they come across.
Tiger sharks are nocturnal moving into inshore, shallow waters to feed at night then back to deeper water during the daytime. They are voracious feeders with reports stating that they will eat anything they come across.
However, a study in Western Australia found the most common foods to be turtles, sea snakes, teleost fishes, dugongs and sea birds. Other research has revealed the tiger sharks main diet to include squid, other shark species, dolphins and molluscs.
Tiger sharks are commercially fished and have been caught for their fins and flesh, although, due to population declines fishing for this species has decreased. As with most other sharks its liver contains a very high vitamin A content, which is used to produce vitamin oil. In some instances the skin is used for the manufacture of leather. Due to its size it is also a highly prized as a big game fish.
The tiger shark is reported to be second only to the great white shark in the number of attacks on humans, however, attacks are rare. During the 1990’s tiger sharks were reportedly responsible for several fatalities Hawaii.
Tiger sharks are commercially fished and have been caught for their fins and flesh, although, due to population declines fishing for this species has decreased. As with most other sharks its liver contains a very high vitamin A content, which is used to produce vitamin oil. In some instances the skin is used for the manufacture of leather. Due to its size it is also a highly prized as a big game fish.
Tiger sharks have been found to have consumed a wide variety of inorganic items that include a roll of tar paper, a rubber tyre, chicken wire, bottles and shoes.