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, mostly living along the coast or offshore in the oceanic environment.
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.
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.
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.
{| class="wikitable collapsible"
|-
! colspan="10"| True Mackerels (tribe Scombrini)
|-
! Common name
! Scientific name
! Maximum<br/>length
! Common<br/>length
! Maximum<br/>weight
! Maximum<br/>age
! Trophic<br/>level
! FishBase
! FAO
! IUCN status
|-
| Short mackerel
| Rastrelliger brachysoma<br /><small>(Bleeker, 1851)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 2.72
| align="center" |
| align="center" |
| VU IUCN 3 1.svg <small>Vulnerable</small>
|-
| Island mackerel
| R. faughni<br /><small>(Matsui, 1967)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 3.4
| align="center" |
| align="center" |
| VU IUCN 3 1.svg <small>Vulnerable</small>
|-
| Indian mackerel
| R. kanagurta<br /><small>(Cuvier, 1816)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 4 years
| align="center" | 3.19
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Blue mackerel
| Scomber australasicus<br /><small>(Cuvier, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.2
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Atlantic chub mackerel
| S. colias<br /><small>(Gmelin, 1789)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |20 years
| align="center" | 3.91
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Chub mackerel
| S. japonicus<br /><small>(Houttuyn, 1782)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 18 years
| align="center" | 3.09
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Atlantic mackerel
| S. scombrus<br /><small>(Linnaeus, 1758)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 12 years west<br />18 years east
| align="center" | 3.65
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|}
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.
{| class="wikitable collapsible"
|-
! colspan="10"| Spanish Mackerels (tribe Scomberomorini)
|-
! Common name
! Scientific name
! Maximum<br/>length
! Common<br/>length
! Maximum<br/>weight
! Maximum<br/>age
! Trophic<br/>level
! FishBase
! FAO
! IUCN status
|-
| Wahoo
| Acanthocybium solandri<br /><small>(Cuvier in Cuvier and Valenciennes, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 9 years
| align="center" | 4.4
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Shark mackerel
| Grammatorcynus bicarinatus<br /><small>(Quoy & Gaimard, 1825)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Double-lined mackerel
| G. bilineatus<br /><small>(Rüppell, 1836)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.18
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Serra Spanish mackerel
| Scomberomorus brasiliensis<br /><small>(Collette, Russo & Zavala-Camin, 1978)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 3.31
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| King mackerel
| S. cavalla<br /><small>(Cuvier, 1829)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 14 years
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Narrow-barred Spanish mackerel
| S. commerson<br /><small>(Lacepède, 1800)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
| align="center" |
| NT IUCN 3 1.svg <small>Near threatened</small>
|-
| Monterrey Spanish mackerel
| S. concolor<br /><small>(Lockington, 1879)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.24
| align="center" |
| align="center" |
| NT IUCN 3 1.svg <small>Near threatened</small>
|-
| Indo-Pacific king mackerel
| S. guttatus<br /><small>(Bloch & Schneider, 1801)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 16 years
| align="center" | 4.28
| align="center" |
| align="center" |
| DD IUCN 3 1.svg <small>Data deficient</small>
|-
| Korean mackerel
| S. koreanus<br /><small>(Kishinouye, 1915)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.2
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Streaked Spanish mackerel
| S. lineolatus<br /><small>(Cuvier, 1829)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Atlantic Spanish mackerel
| S. maculatus<br /><small>(Mitchill, 1815)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 5 years
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Papuan Spanish mackerel
| S. multiradiatus<br /><small>Munro, 1964</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.0
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Australian spotted mackerel
| S. munroi<br /><small>(Collette & Russo, 1980)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.3
| align="center" |
| align="center" |
| NT IUCN 3 1.svg <small>Near threatened</small>
|-
| Japanese Spanish mackerel
| S. niphonius<br /><small>(Cuvier, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
| NT IUCN 3 1.svg <small>Near threatened</small>
|-
| Queen mackerel
| S. plurilineatus<br /><small>Fourmanoir, 1966</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.2
| align="center" |
| align="center" |
| DD IUCN 3 1.svg <small>Data deficient</small>
|-
| Queensland school mackerel
| S. queenslandicus<br /><small>(Munro, 1943)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 10 years
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Cero mackerel
| S. regalis<br /><small>(Bloch, 1793)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Broadbarred king mackerel
| S. semifasciatus<br /><small>(Macleay, 1883)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 10 years
| align="center" | 4.5
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Pacific sierra
| S. sierra<br /><small>(Cuvier, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
|-
| Chinese mackerel
| S. sinensis<br /><small>(Cuvier, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.5
| align="center" |
|-
| West African Spanish mackerel
| S. tritor<br /><small>(Cuvier, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.26
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
{| class="wikitable collapsible"
|-
! colspan="11"| Other mackerel species
|-
! Family
! Common name
! Scientific name
! Maximum<br/>length
! Common<br/>length
! Maximum<br/>weight
! Maximum<br/>age
! Trophic<br/>level
! FishBase
! FAO
! IUCN status
|-
| align="center" rowspan=1 |Scombridae<br /><small>Gasterochisma</small>
| Butterfly mackerel
| Gasterochisma melampus <small>Richardson, 1845</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.4
| align="center" |
| align="center" |
| align="center" | LC IUCN 3 1.svg <small>Least concern</small>
|-
| rowspan="11" align="center" |Carangidae<br /><small>Jack mackerel</small><!-- Just species with mackerel in common name, not all in trachurus genus. Maybe make visible comment? -->
| Mackerel Scad
| Decapterus macarellus <small>(Culiver, 1833)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.0
| align="center" |
| align="center" |
| align="center" | LC IUCN 3 1.svg <small>Least concern</small>
|-
|Atlantic horse mackerel
|Trachurus trachurus <small>(Linnaeus, 1758)</small>
| align="right"|
| align="right"|
| align="right"|
|
| align="center"| 3.64
| align="center"|
| align="center" |
|<small>VU IUCN 3 1.svg Vulnerable</small>
|-
| Blue jack mackerel
| T. picturatus <small>(Bowdich, 1825)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 18 years
| align="center" | 3.32
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Cape horse mackerel
| T. capensis <small>(Castelnau, 1861)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 3.47
| align="center" |
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| Chilean jack mackerel
| T. murphyi <small>(Nichols, 1920)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 16 years
| align="center" | 3.49
| align="center" |
| align="center" |
| DD IUCN 3 1.svg <small>Data deficient</small>
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| Greenback horse mackerel
| T. declivis <small>(Jenyns, 1841)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 25 years
| align="center" | 3.93
| align="center" |
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| Japanese horse mackerel
| T. japonicus <small>(Temminck & Schlegel, 1844)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 12 years
| align="center" | 3.4
| align="center" |
| align="center" |
| align="center" | <small>NT IUCN 3 1.svg Near threatened</small>
|-
| Mediterranean horse mackerel
| T. mediterraneus <small>(Steindachner, 1868)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 3.59
| align="center" |
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| Pacific jack mackerel
| T. symmetricus <small>(Ayres, 1855)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 30 years
| align="center" | 3.56
| align="center" |
| align="center" |
| LC IUCN 3 1.svg <small>Least concern</small>
|-
| Yellowtail horse mackerel
| T. novaezelandiae <small>(Richardson, 1843)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 25 years
| align="center" | 4.5
| align="center" |
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| align="center" rowspan=5 |Gempylidae<br /><small>Snake mackerel</small>
| Black snake mackerel
| Nealotus tripes <small>(Johnson, 1865)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.2
| align="center" |
| align="center" |
| align="center" | LC IUCN 3 1.svg <small>Least concern</small>
|-
| Blacksail snake mackerel
| Thyrsitoides marleyi <small>(Fowler, 1929)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.19
| align="center" |
| align="center" |
| align="center" | <small>Not assessed</small>
|-
| Snake mackerel
| Gempylus serpens <small>(Cuvier, 1829)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.35
| align="center" |
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| Violet snake mackerel
| Nesiarchus nasutus <small>(Johnson, 1862)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 4.33
| align="center" |
| align="center" |
| align="center" | <small>LC IUCN 3 1.svg Least concern</small>
|-
| White snake mackerel
| Thyrsitops lepidopoides <small>(Cuvier, 1832)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" |
| align="center" | 3.86
| align="center" |
| align="center" |
| align="center" | <small>Not assessed</small>
|-
| align="center" rowspan=2 |Hexagrammidae
| Okhotsk atka mackerel
| Pleurogrammus azonus <small>(Jordan & Metz, 1913)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 12 years
| align="center" | 3.58
| align="center" |
| align="center" |
| align="center" | <small>Not assessed</small>
|-
| Atka mackerel
| P. monopterygius <small>(Pallas, 1810)</small>
| align="right" |
| align="right" |
| align="right" |
| align="right" | 14 years
| align="center" | 3.33
| align="center" |
| align="center" |
| align="center" | <small>Not assessed</small>
|}
thumb|right|Still life with mackerel, lemon and tomato, [[Van Gogh, 1886]]
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)
thumb|400px|Like other scombroids, mackerel such as this [[Atlantic mackerel are superb swimmers, and can retract their fins into grooves on their bodies for streamlining. They have deeply forked tails and are smaller and slimmer than tuna.]]
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 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.
thumb|360px|left|Mackerel, such as these [[Pacific jack mackerel, usually have vertical stripes on their sides which provide "schooling marks", visual clues that help them stay in formation as they school.
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,
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)
thumb|right|[[Gannets and other seabirds fuel themselves with mackerel]]
Mackerel are prolific broadcast spawners, and must breed near the surface of the water because the eggs of the females float. Individual females lay between 300,000 and 1,500,000 eggs.
Off Madagascar, spinner sharks follow migrating schools of mackerel. Bryde's whales feed on mackerel when they can find them. They use several feeding methods, including skimming the surface, lunging, and bubble nets.