Blue sharks are among the most abundant and far-ranging of all sharks, found in tropical, subtropical and temperate waters of every ocean. They are known to migrate long distances, and prey primarily on schooling fish such as anchovies, sardines, herring and squid. Blue sharks will, however, attack virtually anything, including gill-netted salmon and wounded marine mammals. Blue sharks were identified and named by Linneaus, the father of modern taxonomy, in 1758, and its common name comes from its dark blue dorsal fin and bright blue sides. Adult blue sharks weigh between 70 to 120 pounds and can grow up to five to seven feet long. They are fished commercially, usually on baited longlines, and by sports fishermen with rods and reels.