Jack mackerels are marine fish in the Trachurus genus of the Carangidae family. The name of the genus derives from the Greek words trachys ("rough") and oura ("tail"). Some species, such as T. murphyi, are harvested in purse seine nets, and overfishing(harvesting beyond sustainable levels) has sometimes occurred.It is often used in Japanese cuisine, where it is called aji, and in Turkish cuisine, where it is called istavrit.