Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, typically in the open ocean but occasionally along the coast. Mackerel species typically have deeply forked tails and vertical "tiger-like" stripes on their backs with an iridescent green-blue quality. Many are restricted in their distribution ranges and live in separate populations or fish stocks based on geography. Some stocks migrate in large schools along the coast to suitable spawning grounds, where they spawn in fairly shallow waters. After spawning they return the way they came in smaller schools to suitable feeding grounds, often near an area of upwelling. From there they may move offshore into deeper waters and spend the winter in relative inactivity. Other stocks migrate across oceans.
Smaller mackerel are forage fish for larger predators, including larger mackerel and Atlantic cod. Flocks of seabirds, whales, dolphins, sharks, and schools of larger fish such as tuna and marlin follow mackerel schools and attack them in sophisticated and cooperative ways. Mackerel flesh is high in omega-3 oils and is intensively harvested by humans. In 2009, over 5 million tons were landed by commercial fishermen. Sport fishermen value the fighting abilities of the king mackerel.
Species Over 30 different species, principally belonging to the family Scombridae, are commonly referred to as mackerel. The term "mackerel" is derived from Old French and may have originally meant either "marked, spotted" or "pimp, procurer". The latter connection is not altogether clear, but mackerel spawn enthusiastically in shoals near the coast, and medieval ideas on animal procreation were creative.
Scombroid mackerels About 21 species in the family Scombridae are commonly called mackerel. The type species for the scombroid mackerel is the Atlantic mackerel, Scomber scombrus. Until recently, Atlantic chub mackerel and Indo-Pacific chub mackerel were thought to be subspecies of the same species. In 1999, Collette established, on molecular and morphological considerations, that these are separate species. Mackerel are smaller with shorter lifecycles than their close relatives, the tuna, which are of the same family.
Scombrini, the true mackerels
The true mackerels belong to the tribe Scombrini. The tribe consists of seven species, each belonging to one of two genera: Scomber or Rastrelliger.
True Mackerels (tribe Scombrini) Common name Scientific name Maximumlength Commonlength Maximumweight Maximumage Trophiclevel FishBase FAO IUCN status Short mackerel Rastrelliger brachysoma(Bleeker, 1851) 2.72 Vulnerable Island mackerel R. faughni(Matsui, 1967) 3.4 Vulnerable Indian mackerel R. kanagurta(Cuvier, 1816) 4 years 3.19 Least concern Blue mackerel Scomber australasicus(Cuvier, 1832) 4.2 Least concern Atlantic chub mackerel S. colias(Gmelin, 1789)20 years 3.91 Least concern Chub mackerel S. japonicus(Houttuyn, 1782) 18 years 3.09 Least concern Atlantic mackerel S. scombrus(Linnaeus, 1758) 12 years west18 years east 3.65 Least concern
Scomberomorini, the Spanish mackerels The Spanish mackerels belong to the tribe Scomberomorini, which is the "cousin tribe" of the true mackerels. This tribe consists of 21 species in all—18 of those are classified into the genus Scomberomorus, two into Grammatorcynus, and a single species into the monotypic genus Acanthocybium.
Spanish Mackerels (tribe Scomberomorini) Common name Scientific name Maximumlength Commonlength Maximumweight Maximumage Trophiclevel FishBase FAO IUCN status Wahoo Acanthocybium solandri(Cuvier in Cuvier and Valenciennes, 1832) 9 years 4.4 Least concern Shark mackerel Grammatorcynus bicarinatus(Quoy & Gaimard, 1825) 4.5 Least concern Double-lined mackerel G. bilineatus(Rüppell, 1836) 4.18 Least concern Serra Spanish mackerel Scomberomorus brasiliensis(Collette, Russo & Zavala-Camin, 1978) 3.31 Least concern King mackerel S. cavalla(Cuvier, 1829) 14 years 4.5 Least concern Narrow-barred Spanish mackerel S. commerson(Lacepède, 1800) 4.5 Near threatened Monterrey Spanish mackerel S. concolor(Lockington, 1879) 4.24 Near threatened Indo-Pacific king mackerel S. guttatus(Bloch & Schneider, 1801) 16 years 4.28 Data deficient Korean mackerel S. koreanus(Kishinouye, 1915) 4.2 Least concern Streaked Spanish mackerel S. lineolatus(Cuvier, 1829) 4.5 Least concern Atlantic Spanish mackerel S. maculatus(Mitchill, 1815) 5 years 4.5 Least concern Papuan Spanish mackerel S. multiradiatusMunro, 1964 4.0 Least concern Australian spotted mackerel S. munroi(Collette & Russo, 1980) 4.3 Near threatened Japanese Spanish mackerel S. niphonius(Cuvier, 1832) 4.5 Near threatened Queen mackerel S. plurilineatusFourmanoir, 1966 4.2 Data deficient Queensland school mackerel S. queenslandicus(Munro, 1943) 10 years 4.5 Least concern Cero mackerel S. regalis(Bloch, 1793) 4.5 Least concern Broadbarred king mackerel S. semifasciatus(Macleay, 1883) 10 years 4.5 Least concern Pacific sierra S. sierra(Cuvier, 1832) 4.5 Least concern Chinese mackerel S. sinensis(Cuvier, 1832) 4.5 Near threatened West African Spanish mackerel S. tritor(Cuvier, 1832) 4.26 Least concern
Other mackerel In addition, a number of species with mackerel-like characteristics in the families Carangidae, Hexagrammidae and Gempylidae are commonly referred to as mackerel. Some confusion had occurred between the Pacific jack mackerel (Trachurus symmetricus) and the heavily harvested Chilean jack mackerel (T. murphyi). These have been thought at times to be the same species, but are now recognized as separate species.
Other mackerel species Family Common name Scientific name Maximumlength Commonlength Maximumweight Maximumage Trophiclevel FishBase FAO IUCN statusScombridaeGasterochisma Butterfly mackerel Gasterochisma melampus Richardson, 1845 4.4 Least concernCarangidaeJack mackerel Mackerel Scad Decapterus macarellus (Culiver, 1833) 4.0 Least concernAtlantic horse mackerelTrachurus trachurus (Linnaeus, 1758) 3.64 Vulnerable Blue jack mackerel T. picturatus (Bowdich, 1825) 18 years 3.32 Least concern Cape horse mackerel T. capensis (Castelnau, 1861) 3.47 Least concern Chilean jack mackerel T. murphyi (Nichols, 1920) 16 years 3.49 Data deficient Cunene horse mackerel T. trecae (Cadenat, 1950) 3.49 Least concern Greenback horse mackerel T. declivis (Jenyns, 1841) 25 years 3.93 Least concern Japanese horse mackerel T. japonicus (Temminck & Schlegel, 1844) 12 years 3.4 Near threatened Mediterranean horse mackerel T. mediterraneus (Steindachner, 1868) 3.59 Least concern Pacific jack mackerel T. symmetricus (Ayres, 1855) 30 years 3.56 Least concern Yellowtail horse mackerel T. novaezelandiae (Richardson, 1843) 25 years 4.5 Least concernGempylidaeSnake mackerel Black snake mackerel Nealotus tripes (Johnson, 1865) 4.2 Least concern Blacksail snake mackerel Thyrsitoides marleyi (Fowler, 1929) 4.19 Not assessed Snake mackerel Gempylus serpens (Cuvier, 1829) 4.35 Least concern Violet snake mackerel Nesiarchus nasutus (Johnson, 1862) 4.33 Least concern White snake mackerel Thyrsitops lepidopoides (Cuvier, 1832) 3.86 Not assessedHexagrammidae Okhotsk atka mackerel Pleurogrammus azonus (Jordan & Metz, 1913) 12 years 3.58 Not assessed Atka mackerel P. monopterygius (Pallas, 1810) 14 years 3.33 Not assessed
The term "mackerel" is also used as a modifier in the common names of other fish, sometimes indicating the fish has vertical stripes similar to a scombroid mackerel:
Mackerel icefish—Champsocephalus gunnari Mackerel pike—Cololabis saira Mackerel shark—several species Shortfin mako shark—Isurus oxyrinchus Mackerel tuna—Euthynnus affinis Mackerel tail goldfish—Carassius auratus
By extension, the term is applied also to other species such as the mackerel tabby cat, and to inanimate objects such as the altocumulus mackerel sky cloud formation.
Characteristics (Scombridae)
Most mackerel belong to the family Scombridae, which also includes tuna and bonito. Generally, mackerel are much smaller and slimmer than tuna, though in other respects, they share many common characteristics. Their scales, if present at all, are extremely small. Like tuna and bonito, mackerel are voracious feeders, and are swift and manoeuvrable swimmers, able to streamline themselves by retracting their fins into grooves on their bodies. Like other scombroids, they lack a swim bladder, and their bodies are cylindrical with numerous finlets on the dorsal and ventral sides behind the dorsal and anal fins, but unlike the deep-bodied tuna, they are slim.
The type species for scombroid mackerels is the Atlantic mackerel, Scomber scombrus. These fish are iridescent blue-green above with a silvery underbelly and near-vertical wavy black stripes running along their upper bodies.
The prominent stripes on the back of mackerels seemingly are there to provide camouflage against broken backgrounds. That is not the case, though, because mackerel live in midwater pelagic environments which have no background. However, fish have an optokinetic reflex in their visual systems that can be sensitive to moving stripes. For fish to school efficiently, they need feedback mechanisms that help them align themselves with adjacent fish, and match their speed. The stripes on neighbouring fish provide "schooling marks", which signal changes in relative position. The lateral line also helps with orderly schooling.
A layer of thin, reflecting platelets is seen on some of the mackerel stripes. In 1998, E J Denton and D M Rowe argued that these platelets transmit additional information to other fish about how a given fish moves. As the orientation of the fish changes relative to another fish, the amount of light reflected to the second fish by this layer also changes. This sensitivity to orientation gives the mackerel "considerable advantages in being able to react quickly while schooling and feeding."
Mackerel range in size from small forage fish to larger game fish. Coastal mackerel tend to be small. The king mackerel is an example of a larger mackerel. Most fish are cold-blooded, but exceptions exist. Certain species of fish maintain elevated body temperatures. Endothermic bony fishes are all in the suborder Scombroidei and include the butterfly mackerel, a species of primitive mackerel.
Mackerel are strong swimmers. Known in the latin family as "punctualis piscis" which translates to "punctual fish." This is due to its punctuality of migration during mating season as it moves from warm to cold waters. Atlantic mackerel can swim at a sustained speed of 0.98 m/sec with a burst speed of 5.5 m/sec, while chub mackerel can swim at a sustained speed of 0.92 m/sec with a burst speed of 2.25 m/sec. The Wahoo (Acanthocybium solandri) has been known to reach speeds of up to .
Distribution
Most mackerel species have restricted distribution ranges, while others, like the Wahoo, are found in all oceans between 59°N and 48°S.
In combination, these fish (Scombroids) can be found worldwide in all oceans of the world, excluding the Southern and Arctic Oceans. However, the Atlantic chub mackerel has been spotted near Greenland in the Arctic Ocean on rare occasions as global warming makes the Arctic more habitable for them.
Some mackerel species, especially pelagic and filter feeding one such as chub mackerel, migrate vertically, staying at certain depths depending on the time of day and food availability.
For example, adult snake mackerel, conduct a diel vertical migration, staying in deeper water during the day and rising to the surface at night to feed. The young and juveniles also migrate vertically, but in the opposite direction, staying near the surface during the day and moving deeper at night.
Lifecycle and ecology (Scombroids)