The Blue shark is a species of requiem shark that inhabits deep waters in the world s temperate and tropical oceans. It lives as far north as Norway and as far south as Chile. Blue sharks are found off the coasts of every continent, except Antarctica. They are known to migrate long distances. The Blue shark is a species of requiem shark that inhabits deep waters in the world s temperate and tropical oceans. It lives as far north as Norway and as far south as Chile. Blue sharks are found off the coasts of every continent, except Antarctica. They are known to migrate long distances. Blue sharks are slim bodied with long pectoral fins. The top of the body is deep blue, lighter on the sides, and the underside is white. It grows to 3.8 meters (12.5 ft) long and can weigh up to 204 kilograms (450 lb). The highest reported weight was 391 kilograms (860 lb) Blue sharks are not considered an aggressive species and rarely attack humans. As of 2009 there have been 13 known attacks on humans and 4 fatalities. Blue sharks give birth to live young and have litters of between 25 to 100 pups. The gestation period is between 9 and 12 months. Females mature at 5 to 6 years of age and males at 4 to 5. Courtship is believed to involve biting by the male. Female blue sharks have adapted to the rigorous mating ritual by developing skin 3 times thicker than male skin. They feed primarily on small fish and squid, although they can take larger prey. Squid are important as food for blue sharks. Their diet includes other invertebrates such as cuttlefish and pelagic octopuses, as well as lobster, shrimp, crab, a large number of bony fishes, small sharks, mammalian carrion and occasional sea birds. Whale and porpoise blubber and meat have been found in Blue shark. They are also known to take fish from trawl nets. Adult blue sharks do not suffer predation on a regular basis, except by humans. Blue sharks are the most heavily fished sharks mainly as by-catch. It is estimated that 10 to 20 million individuals are killed each year as a result of fishing. The flesh is edible and it is consumed fresh, dried, smoked and salted and diverted for fish meal. The skin is used for leather, the fins for shark-fin soup and the liver for oil. Blue sharks are occasionally sought as game fish for their speed and fight. Young and smaller individuals may get eaten by larger sharks such as the Great White Shark and the Tiger Shark.
