A forensic study into shark DNA has revealed that many of the hammerhead sharks used to make shark-fin soup started life in American waters. “For the first time, scientists have used DNA from shark fins to determine where they came from. The researchers traced finds from the scalloped hammerhead shark species—collected at the world's biggest fin market in Hong Kong—back to rare populations in the Atlantic and Indo-Pacific oceans. The trade in shark fins supplies Asian markets with the key ingredient in the luxury dish shark-fin soup. The practice claims up to 73 million sharks annually, including up to 3 million hammerheads. The finless fish are usually tossed back into the ocean to die. Because the vast flow of shark fins to global markets usually operates in secret, conservationists have been left in the dark about where the sharks are killed. And governments can't control the trade if they don't know how many sharks are being taken from their waters.”