![]() Records from the Atlantic show a regular clockwise migration within the prevailing currents. It prefers water temperatures between 12 and 20 ☌ (54–68 ☏), but can be seen in water ranging from 7 to 25 ☌ (45–77 ☏). ![]() In the tropics, it spreads evenly between 20° N and 20° S. Its greatest Pacific concentrations occur between 20° and 50° North, but with strong seasonal fluctuations. Blue sharks are found off the coasts of every continent, except Antarctica. It lives as far north as Norway and as far south as Chile. In temperate seas it may approach shore, where it can be observed by divers while in tropical waters, it inhabits greater depths. The blue shark is an oceanic and epipelagic shark found worldwide in deep temperate and tropical waters from the surface to about 350 m (1,150 ft). Female blue sharks have adapted to the rigorous mating ritual by developing skin three times as thick as male skin. Courtship is believed to involve biting by the male, as mature specimens can be accurately sexed according to the presence or absence of bite scarring. Females mature at five to six years of age and males at four to five. The gestation period is between 9 and 12 months. They are viviparous, with a yolk-sac placenta, delivering 4 to 135 pups per litter. The blue shark is also ectothermic and it has a unique sense of smell. The heaviest reported weight for the species was 391 kg (862 lb). Occasionally, a female in excess of 3 m (9.8 ft) will weigh over 204 kg (450 lb). The blue shark is fairly elongated and slender in build and typically weighs from 27 to 55 kg (60 to 121 lb) in males and from 93 to 182 kg (205 to 401 lb) in large females. Occasionally, an outsized blue shark is reported, with one widely printed claim of a length of 6.1 m (20 ft), but no shark even approaching this size has been scientifically documented. Large specimens can grow to 3.8 m (12 ft) long. The male blue shark commonly grows to 1.82 to 2.82 m (6.0 to 9.3 ft) at maturity, whereas the larger females commonly grow to 2.2 to 3.3 m (7.2 to 10.8 ft) at maturity. Like many other sharks, blue sharks are countershaded: the top of the body is deep blue, lighter on the sides, and the underside is white. Anatomy and appearance īlue sharks are light-bodied with long pectoral fins. Maximum lifespan is still unknown, but it is believed that they can live up to 20 years. They feed primarily on small fish and squid, although they can take larger prey. Blue sharks are viviparous and are noted for large litters of 25 to over 100 pups. It is listed as Near Threatened by the IUCN.Īlthough generally lethargic, they can move very quickly. Averaging around 3.1 m (10 ft) and preferring cooler waters, the blue shark migrates long distances, such as from New England to South America. They are currently listed as a vulnerable species however, they continue to be hunted in parts of Asia, such as the Philippines.The blue shark ( Prionace glauca), also known as the great blue shark, is a species of requiem shark, in the family Carcharhinidae, which inhabits deep waters in the world's temperate and tropical oceans. The coral spawning of the area's Ningaloo Reef provides the whale shark with an abundant supply of plankton.Īlthough massive, whale sharks are docile fish and sometimes allow swimmers to hitch a ride. They are known to migrate every spring to the continental shelf of the central west coast of Australia. Preferring warm waters, whale sharks populate all tropical seas. Its two dorsal fins are set rearward on its body, which ends in a large dual-lobbed caudal fin (or tail). Its back and sides are gray to brown with white spots among pale vertical and horizontal stripes, and its belly is white. The whale shark's flattened head sports a blunt snout above its mouth with short barbels protruding from its nostrils. The mechanism is theorized to be a technique called “cross-flow filtration,” similar to some bony fish and baleen whales. In order to eat, the beast juts out its formidably sized jaws and passively filters everything in its path. The whale shark, like the world's second largest fish, the basking shark, is a filter feeder. They scoop these tiny plants and animals up, along with any small fish that happen to be around, with their colossal gaping mouths while swimming close to the water's surface. Fortunately for most sea-dwellers-and us!-their favorite meal is plankton. As the largest fish in the sea, reaching lengths of 40 feet or more, whale sharks have an enormous menu from which to choose.
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