Galeus glaucus now called Prionace glauca the blue shark by BioDivLibrary on Flickr.
Blue sharks give birth to live young and can deliver up to 135 pups per litter. 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 rigorous mating ritual by developing skin 3 times thicker than male skin.
The blue shark is listed as Near Threatened by the IUCN
The Plagiostomia : Sharks, skates, and rays
Cambridge, U.S.A. :Printed for the Museum,1913.