mackerel fish

The common mackerel (Scomber scombrus) of the Atlantic Ocean is an abundant and economically important species that is sometimes found in huge schools. It averages about 30 cm (12 inches) in length and is blue-green above and silver-white below, with a series of wavy, dark, vertical lines on the upper sides. It has two well-separated dorsal fins and two small keels on either side of the tail base; it lacks an air bladder. The common mackerel occurs along both coasts of the North Atlantic Ocean, from North Carolina to Labrador and from Spain to Norway.