Blue shark

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. It is the only living species of genus Prionace. An extinct species, P. clarki, is known from teeth from California of the Late Pliocene. 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. It is listed as Near Threatened by the IUCN. Although generally lethargic, they can move very quickly. Blue sharks are viviparous and are noted for large litters of 25 to over 100 pups. They feed primarily on small forage fish and squid, although they can take larger prey. Some of the blue shark's predators include the killer whale and larger sharks like the tiger shark and the great white shark. Their maximum lifespan is still unknown, but it is believed that they can live up to 20 years. They are one of the most abundant pelagic sharks, with large numbers being caught by fisheries as bycatch on longlines and nets. The earliest fossil teeth of this species are known from the Miocene of Sri Lanka. Other fossil teeth of this species are known from the Miocene and Pliocene of Chile, Italy, and possibly Belgium.