The double-lined mackerel (Grammatorcynus bilineatus), is a species of Spanish mackerel (tribe Scomberomorini) in the family Scombridae. It is a commercial fish and is distributed from the Red Sea to the Andaman Sea, also from the northern coast of Australia to the Ryukyu Islands, as far as Fiji. It is mostly found in shallow waters.This species is sometimes also called the scad mackerel. Before 1983, this species was sometimes confused with Grammatorcynus bicarinatus, the shark mackerel.