Atlantic Mackerel

Overview

The Atlantic mackerel is a highly migratory, pelagic fish widely distributed across the temperate waters of the North Atlantic, Mediterranean, and Black Seas. Known for its speed and agility, this species forms massive schools that move inshore during warmer months to feed before migrating to deeper, offshore waters as temperatures drop.

Appearance

This streamlined, spindle-shaped fish is easily recognized by its iridescent blue-green back, which is marked with 20 to 30 distinct, wavy black stripes. Its underside is a clean, silvery-white. It features two widely spaced dorsal fins, a pointed snout, and a deeply forked, crescent-shaped tail. Notably, it lacks a swim bladder, requiring it to swim constantly to maintain its position in the water column.

Biology & behavior

Atlantic mackerel are diurnal, active predators that rely on their schooling behavior to increase hunting efficiency. They are long-lived, capable of surviving for 20 years or more. Because they lack a swim bladder, they are perpetual swimmers. During the winter, they enter a period of reduced activity and fasting in deeper, warmer offshore environments.

Feeding

As opportunistic carnivores, their diet shifts as they grow. Juveniles primarily consume zooplankton, such as copepods. Adults maintain a varied diet that includes larger crustaceans, fish larvae, and small schooling fish like herring, sprats, and sand eels.

Reproduction

Spawning is an external process that occurs in spring and summer when water temperatures reach approximately 11–14°C. Females are batch spawners, releasing large quantities of eggs that drift freely in the water column. The larvae hatch after a few days and continue to develop while drifting with plankton.