Mackerel, a general name for fish of the Acanthopterygian family Scombridae, which includes many valuable food-fishes. The species are abundant in all tropical and temperate seas. The elongated, generally spindle-shaped body is naked or covered with small scales; two dorsal fins and, usually, finlets are present. They are extremely active, and wander in large shoals, approaching the coast periodically, probably in pursuit of the smaller fishes on which they feed. The type-genus Scomber, with seven species, has nearly the range of the family, but is absent from the eastern shores of South America. The body is covered with small scales, and there are finlets behind the dorsal and anal fins. S. scomber, the Common Mackerel, ranges over the north Atlantic Ocean and the North Sea. It is a very valuable food fish, of an average length of about fifteen inches, shapely in form, and beautiful in coloration. The upper surface is greenish-blue, with vertical black bars; below the hue is silvery white. The British mackerel-fishery is an important industry. The first shoals appear early in the year, and about the end of May, when the fish are in the best condition, immense numbers are met off the Scilly Isles. The bulk of these come up Channel, but some go northwards into the Irish Sea. Nets are chiefly used in their capture, but very many are taken with lines baited with anything bright. They spawn at some distance from land, and the eggs float on the surface. S. colias, the Spanish Mackerel, sometimes taken on the Cornish coast, is spotted on the sides, and differs from the Common Mackerel in having a swim-bladder.