More you should know:
Atlantic mackerel is extremely high in vitamin B12 as well as omega 3 fatty acids and contains nearly twice as much of the latter per unit weight as salmon. Unlike the King and Spanish species, Northern Atlantic mackerel are very low in mercury. In many countries, canned mackerel in tomato sauce, brine, or vegetable oil is sometimes eaten with salad or in sandwiches. Mackerel is an excellent source of phosphatidylserine, as it contains about 480 mg / 100 grams by weight.
*Other Mackerel species available: Scomber japonicus, Scomber colias, Trachurus trachurus (Horse Mackerel)
Abundant in cold and temperate shelf areas, it forms large schools near the surface. They overwinter in deeper waters but move closer to shore in spring when water temperatures range between 11 and 14 °C (52 and 57 °F).
Atlantic Mackerel is found in the north-east Atlantic: North Sea (east) and British Isles (west). (information credit, wikipedia)