mackerel, common name for members of the family Scombridae, 60 species of open-sea fishes, including the albacore, bonito, and tuna. They are characterized by deeply forked tails that narrow greatly where they join the body; small finlets behind both the dorsal and the anal fins; and sleek, streamlined bodies with smooth, almost scaleless skins having an iridescent sheen. All members of the mackerel family are superb, swift swimmers. The firm, oily texture of their powerful muscles and their generally large size make them of great commercial importance as food fish. They travel in schools, feeding on other fish (chiefly herring) and on squid, and migrate between deep and shallow waters. The smaller species rely on the constant rush of water through their gills for sufficient oxygen and will suffocate if motionless. The largest of the family, the enormous (up to 3/4 ton/680 kg) tunas, are among the few warm-blooded fishes, due to the constant operation of their huge banks of muscles. Of the smaller members of the family, the Atlantic, or common, mackerel, Scomber scombrus, found in colder waters off North America and Europe, is one of the smallest (11/2 lb/0.675 kg average). Despite its size, the annual catch is 50 million lb (22.5 million kg), which is marketed fresh, salted, and canned. Intermediate between the Atlantic mackerel and the bonitos (see tuna) are the frigate mackerels, found in warm seas. Spotted species found off the Florida and Gulf coasts include the Spanish, painted, and Sierra mackerels, averaging 10 to 15 lb (4.5–6.7 kg). Other species are the king mackerel, also called kingfish and cero (up to 60 lb/27 kg); the chub mackerel, similar to the Atlantic mackerel; and the cosmopolitan and more solitary wahoo, or peto. Related to the mackerels are the escolars and rabbit fishes of Mediterranean and Cuban waters and the cutlass, or scabbard, fish, a degenerate eellike offshoot of the mackerels, found off the coast of Florida. Mackerels are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Perciformes, family Scombridae.