Atlantic mackerel is easily recognized by its blue/green tiger-like back stripes. It has an average length of about 30 – 40 cm, although it can grow up to 70 cm. Mackerel is a fast swimmer and needs to be in constant motion in order not to sink, as it doesn’t have a swim bladder. Atlantic mackerel is a predatory fish that feeds on krill, crustaceans, small fish and is even prone to cannibalism.
It is a migratory fish. It spawns just east of the Irish coast during spring then migrates north-west towards Iceland in the early summer. In late summer to early fall it moves eastward towards Norway. From fall to winter the it travels south along the Norwegian coast to the North Sea. During the winter it heads back west to the Irish coast for spawning. Consequently, Atlantic mackerel is always close to the Faroe Islands during its annual migration.
A female mackerel can spawn up to 450.000 eggs in a single spawning season. The hatching time depends on sea temperature. Most Atlantic mackerel spawn in temperate waters at about 9 – 12 °C.
At this temperature hatching usually takes about a week. The newly hatched larvae are incapable of swimming, instead, they drift with the pelagic current for a month. Then enters the post-larval stage. At night the young mackerel go to the surface to feed, during the day they descend deeper into the ocean to avoid natural predators. After approx. 40 days the Atlantic mackerel has grown to about 5 cm in length. At this stage, the young mackerel as taken on the distinct mackerel shape and colors, and they join other mackerel in the annual migration. Atlantic mackerel reaches sexual maturity at 2 years of age and can live up to 17 years.