The blue shark, Prionace glauca, is a carcharhinid shark which is found in the deep waters of the world's temperate and tropical oceans. They prefer cooler waters and are not found, for example, in the Yellow Sea or in the Red Sea. Blue sharks are known to migrate long distances, from New England to South America for example. Although generally lethargic, they are capable of moving very quickly if the need arises. Blue sharks are viviparous and are noted for their large litters of 25 to over 100 pups. They feed primarily on small fish and squid, although they are perfectly capable of taking larger prey should the opportunity present itself. Also, they may pose considerable danger to humans if they are encountered in large groups. They are often found in schools segregated by sex and size, and this behavior has led to their being nicknamed the "wolves of the sea". They are also the second fastest sharks, next to the mako shark.
Blue sharks are light-bodied with long pectoral fins. The top of the body is deep blue, lighter on the sides, and the underside is white. The animal grows to 3.8 m (12.5 ft) or more. The shark's typical weight is 136 kg (300 lb) to 182 kg (400 lb) and can grow to 205 kg (450 lb). The highest reported weight was 391 kg (861 lb). They are rarely confused with other sharks.
Adult blue sharks do not suffer predation on a regular basis, except by humans. Young and smaller individuals may get eaten by any sufficiently large carnivore. However, they are host to several species of parasites. For example, the blue shark is the definite host of the tetraphyllidean tapeworm, Pelichnibothrium speciosum (=Prionacestus bipartitus). They become infected by eating the intermediate hosts, probably Opah, Lampris guttatus, and/or longnose lancetfish, Alepisaurus ferox (Scholz et al. 1998).
They are vivaporous, with a yolk-sac placenta, delivering 4 to 135 pups per litter. 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, as mature specimens can be accurately sexed according to the presence or absence of bite scarring. Female blue sharks have adapted to the rigours of the mating ritual by developing skin 3 times as thick as that of males.
Conversely, blue sharks rarely attack humans. While they are one of the 20 or so species of shark considered dangerous they rate on the low end of that spectrum. Most interaction between blue sharks and humans takes place in deep water as they rarely venture close to shore. As of 2008, there are only 4 records of Blue Shark related human fatalities.
Effects of recreational and commercial fishing on blue sharks (Prionace glauca) in Atlantic Canada, with inferences on the North Atlantic population.
Mar 01, 2006; Abstract: The nominal catch of blue sharks (Prionace glauca) reported for the Canadian Atlantic grossly underestimates the annual...
Reproductive Biology of the Blue Shark Prionace Glauca (Chondrichthyes: Carcharhinidae) off Baja California Sur, Mexico
Jul 15, 2010; INTRODUCTION The blue shark Prionace glauca (Linnaeus, 1758) is one of the most abundant pelagic sharks and is the most widely...
Length at maturity in three pelagic sharks (Lamna nasus, Isurus oxyrinchus, and Prionace glauca) from New Zealand.
Jul 01, 2005; Abstract--Reproductive data collected from porbeagle, shortfin mako, and blue sharks caught around New Zealand were used to...