quality:correction
Characteristics

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, 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.

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.