Aliases: Alaska King Crab , Echizen Crab, Cod Farm Crab, Kamchatka Rock Crab. King crabs, also known as emperor crabs, rock crabs or rock crabs, are crustaceans of the rock crab family. They are mainly distributed in cold waters. It is named after its huge size and is known as the “king of crabs”. Because of their huge size and delicious meat, many species are widely caught as food, the most common of which is the Kamchatka stone crab.