A member of the requiem shark family, the blue shark is very slender and streamlined, with a long and pointed snout that is much longer than the width of its mouth.
Appropriately, it is a deep, brilliant blue or a dark cobalt to indigo blue above, fading gradually to white below. With up to three rows of functional teeth in each jaw, the larger teeth in the upper jaw are “saber shaped,” or broadly convex on one side and concave on the other; the teeth are serrated along the edges, and those in the lower jaw are narrower.
Circumglobal in temperate and tropical waters, blue sharks hardly rate as fighters in comparison to makos and threshers, but they are much more abundant and provide fine sport on appropriate tackle in cooler temperate waters off the northeastern United States, England, and California, where there are large sportfisheries for them.
They usually swim slowly, and yet they can be one of the swiftest sharks. The largest fish exceed 400 pounds and are fairly strong fighters when taken from cool waters.
Viviparous, blue sharks bear live young in large litters, up to 54 at one time (135 have been recorded); they mature at a length of 7 or 8 feet but can reach upward of 13 feet. The all-tackle world record is a 528-pound fish taken off Montauk, New York, in 2001.
Blue sharks are potentially dangerous to humans because they are related to unprovoked attacks on both humans and boats, especially during accidents and disasters at sea when injured people are in the water. They are sometimes called blue whalers because of their habit of trailing whaling ships and feeding off whale carcasses and ship garbage.