Tiger Sharks

Tiger Sharks (Galeocerdo cuvier)

 

The tiger shark is one of the largest sharks in the ocean, capable of attaining a length of over 5 m (16 ft). This shark typically reaches maturity at lengths of 2 to 3 m (6.6 to 9.8 ft) and weighs around 385–635 kilograms (849–1,400 lb). Tiger sharks are ovoviviparous, which means the shark eggs are fertilized and carried within the mother. They are born in litters between 30 and 55 pups, while pregnancy last between 15 and 16 months.  At birth the pups are 20 to 30 inches (50-75 cm) and completely independent. Females mate once every three years.

Tiger sharks are seasonal visitors to the island, with the largest numbers found at Argus and Challenger banks between the months of July and October. The sharks move north for the summer and often east of Bermuda, some staying well out in open water.  In the winter the sharks move south towards the Bahamas or Caribbean for months in close association with island habitats.

Tiger sharks are found in tropical and sub-tropical waters and they usually hunt alone and feed primarily at night. This shark eats fish, seals, squid, birds, turtles, stingrays, sea snakes and they also eat other sharks. These beautiful sharks have special gill slit (spiracle) behind the eyes that provides oxygen flow directly to the eyes and brain. They also have really good eyesight and great sense of smell. Tiger sharks' skins can typically range from blue to light green with a white or light yellow underbelly. Dark spots and stripes are most visible in young sharks and fade as the shark matures. Its teeth are specialized to slice through flesh, bone, and other tough substances such as turtle shells. Like most sharks, however, its teeth are continually replaced by rows of new teeth.

The tiger shark is captured and killed for its fins, flesh, and liver. It is caught regularly in target and non-target fisheries. There is evidence of declines for several populations where they have been heavily fished, but in general they do not face a high risk of extinction. However, continued demand, especially for fins, may result in further declines in the future. Tiger sharks are considered a near threatened species due to excessive finning and fishing by humans according to International Union for Conservation of Nature (IUCN). While shark fin has very few nutrients, shark liver has a high concentration of vitamin A which is used in the production of vitamin oils. In addition, the tiger shark is captured and killed for its distinct skin, as well as by big game fishers.

 By Dept. Conservation Services Summer student Mr. Edwin Dill - thanks Edwin!