Blue shark

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.

Basking Shark

The basking shark is the second largest living fish, after the whale shark.  The basking shark is the second largest living fish, after the whale shark. The largest accurately-measured specimen was trapped in a herring net in the Bay of Fundy, Canada in 1851. Its total length was 12.27 metres (40.3 ft), and it weighed an estimated 19 tonnes. On average, the adult basking shark reaches a length of 6 to 8 metres (20 to 26 ft) and weighs about 5.2 tonnes. Some specimens still grow to 9 to 10 metres (30 to 33 ft), but after years of large-scale fishing, specimens of this size have become rare. Basking sharks are not aggressive and generally harmless to people. It is a found in all the world s temperate oceans. It is a slow moving and generally harmless filter feeder with a greatly enlarged mouth. The basking shark is usually greyish-brown in colour and often seems to have a mottled appearance. The tail fin has a strong lateral keel and a crescent shape. The teeth of the basking shark are very small and numerous and often number one hundred per row. The teeth themselves have a single conical cusp, are curved backwards and are the same on both the upper and lower jaws. The basking shark is a coastal-pelagic shark found world wide It prefers 8 to 14.5  °C (46 to 58  °F) temperatures, but recently has been confirmed to cross the much-warmer waters at the equator. It is often seen close to land, including bays with narrow openings. It follows plankton concentrations in the water column and is often visible at the surface. The basking shark is found from the surface down to at least 910 metres (2,990 ft). Basking sharks are a migrating species and are believed to over winter in deep waters. It has long been a commercially important fish, as a source of food, shark fin, animal feed, and shark liver oil. Over exploitation has reduced its populations to the point that some have apparently disappeared and others need protection. Mating is thought to occur in early summer and birthing in late summer, following the female s movement into shallow waters. Gestation is thought to span over a year (perhaps two to three years), with a small, though unknown, number of young born fully developed at 1.5 to 2 metres (4 ft 10 in to 6 ft 7 in). Only one pregnant female is known to have been caught; she was carrying six unborn young.