DISTINGUISHING FEATURES AND BEHAVIORS

Sharks, skates, and rays belong to a particular group of fish called elasmobranchs, meaning their entire skeleton is made of cartilage rather than bone.

The blue shark is distinguishable from other sharks because it has a slender body and long, narrow pectoral fins. Its body is thickest at the midsection and tapers toward the head and tail. This shark has two dorsal fins, the second about half the size of the first, and an asymmetrical tail.

The blue shark gets its name from its distinctive blue coloring that fades to white on its underside. When it dies, the blue coloring of the skin fades to gray. The tough skin is composed of hard scales, called dermal denticles, that are abrasive when rubbed against the grain. Five or more gill openings can be seen on the sides of the head.

The snout of the blue shark is long with a well-rounded tip. It has large, pointed, serrated teeth that are well developed and packed close together in its mouth. The blue shark feeds on fish smaller than itself, such as herring, spiny dogfish, and mackerel. It is also a scavenger, feeding on the dead carcasses of fish, whales and other sharks.

The blue shark is often seen swimming lazily at the surface, basking in the sun, and is not believed to swim to great depths. However, it is capable of attaining great speeds. The blue shark is highly migratory and found in all of the world's oceans.

RELATIONSHIP TO PEOPLE

The blue shark is the most abundant of oceanic sharks. Its presence in Narragansett Bay waters is rare, but they have been spotted near the mouth of the Bay while migrating up and down the Atlantic coastline. Some species of sharks are considered dangerous to people, but these encounters are extremely rare.

Like most pelagic shark species, the blue shark population is severely threatened by overfishing. Recent discoveries about the use of cartilage to cure cancer has lead to an increase in harvesting of these slow-growing fish.

The practice of "finning" has leveled the populations of many species of oceanic sharks, including the blue shark. Finning is the cruel practice where the fins are removed from the shark and the animal is released alive. Shark fin soup is considered a delicacy in many Asian countries.