Mackerel is the rich, oily, blue-and-silver flesh of fast-swimming pelagic fish of the family Scombridae — above all the Atlantic mackerel (Scomber scombrus), banded across the back with iridescent steel-blue tiger stripes. Among the oiliest of common food fishes, its flesh is dense in omega-3 oils, deeply savoury and pronouncedly marine, with a soft pinkish-grey raw meat that firms and flakes pale when cooked. Smelling frankly of the sea and tasting bold, fatty and almost meaty, it is grilled whole over coals, smoked, tinned, and — as the chub mackerel saba — pressed into some of the most prized sushi in Japan.