Tiger Shark

Tiger Shark 1Sharks often conjure a feeling of awe and respect as these apex predators seem to rule the oceans. With bodies constructed for chasing prey, sharks are streamlined to enable fast swimming and have excellent senses of sight and smell. The Tiger Shark (Galeocerdo cuvier), a large fish that is sometimes feared for its aggressive behavior, has earned a nickname that is far from prestigious: “wastebasket of the sea”. Tiger Sharks are known as scavengers that will eat just about anything: stingrays, dolphins, sea snakes, seals, squids, fish, turtles, crabs, clams, mammals, sea birds, reptiles, other sharks, and even human rubbish such as bottles, pieces of boats and ships, old tires and license plates. No other species of shark has such a wide variety of prey. This diet helps control the health of ocean ecosystems, by scavenging weak and sick individuals from a multitude of species.  Tiger sharks feed alone at night, close to shore, retreating to deeper waters during the day.

Another feature that sets the Tiger Shark apart is that it is the only species in its family (Carcharhinidae) that is ovoviviparous. This means that Tiger Shark embryos are fertilized and develop in a brood chamber inside the female and are nourished by a yolk sac. After a gestation period that lasts between 14 and 16 months, the young are born live in litters of between 10 and 82 pups, and are fully developed and independent. They receive no help from their mother to find food or to fight off predators. Males and females do not form exclusive bonds but have several mates, with females mating about every three years. In the Northern Hemisphere, mating takes place between March and May.

Tiger Shark 2Young Tiger Sharks have tiger-stripe markings on their bodies that give this species its common name, however these markings fade in adults and become absent in adults over three metres long. Adult Tiger Sharks are blue-green to dark grey in color with a white to light yellow belly. They have a long and thick body that becomes more slender towards the tail. The fourth largest shark in the world, Tiger Sharks commonly reach a length between 3.25 and 4.25 metres and weigh between 385 and 635 kilos. They have a large head with a short, blunt snout and a mouth that is wider than other sharks in its family. The large first dorsal fin is much longer than the second dorsal fin and the upper lobe of the tail fin is long and pointed.

Tiger Sharks live both in coastal and pelagic waters, up to depths of about 350 metres. They tend to prefer murky waters in coastal areas. They also frequent river estuaries, corals reefs and lagoons. Tiger Sharks have very large home ranges. Individuals attached with transmitters swam up to 16 kilometres in a single day and did not return to that area for close to a year. They also migrate seasonally; in summer they move to temperate waters and return to the tropics in winter. The Tiger Shark is classified as Near Tiger Shark 3Threatened throughout its range under the IUCN Red List of Threatened Species. It is targeted in a number of commercial fisheries for its meat, skin and fins. Its liver is also sought after as it contains high levels of vitamin A, which is processed into vitamin oil. Tiger Sharks are also a popular big game fish. A number of shark sanctuaries have been established in the Pacific (Palau, Tokelau, Marshall Islands, Cook Islands, French Polynesia, New Caledonia), Indian Ocean (The Maldives, Raja Ampat) and the Caribbean region (Honduras, The Bahamas, British Virgin Islands) to help protect Tiger Sharks and other shark species from exploitation.

 


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