Scomber scombrus
The Atlantic mackerel (*Scomber scombrus*), also known as mackerel, is a high-speed pelagic fish essential for marine ecosystems and the fishing economy. Unlike the Danube shad, it does not enter fresh waters, remaining strictly in the marine environment. It is a tireless swimmer that covers huge distances in search of food, being highly valued for its meat rich in Omega-3 fatty acids.
The body is fusiform, aerodynamic and covered with very small, almost invisible scales, giving it a silky texture. The back is metallic blue-green, marked by numerous black, sinuous lines that provide excellent camouflage against aerial predators. The belly is silvery-white, without spots. An important detail is the absence of a swim bladder, which forces it to swim continuously to avoid sinking and to breathe efficiently.
This species occupies the temperate waters of the North Atlantic Ocean, Mediterranean and Black Sea. In the Romanian sector of the Black Sea, the mackerel appears in large schools, migrating seasonally between wintering and feeding areas near the coast. In the Danube Delta area, it can be encountered in the marine waters off the river mouths, where nutrients brought by the river stimulate plankton production.
The Atlantic mackerel is a gregarious fish that forms compact schools, sometimes made up of thousands of individuals. It is an active consumer of plankton (especially copepods), but as it grows, the diet diversifies to include anchovy or sprat fry. Feeding is by filtration or individual capture of prey, with schools moving rapidly in the upper layer of the water column.
Sexual maturity is reached at 2-3 years of age. Reproduction takes place in spring and early summer, in coastal waters. A single female can lay between 200,000 and 450,000 pelagic eggs that float in the surface layers of the water. Larvae hatch quickly, in a few days depending on water temperature, and have a very high growth rate in the first year of life.
Globally, the species is classified as Least Concern (LC). However, populations are closely monitored due to extreme commercial pressure. In the Black Sea, stocks have suffered major historical fluctuations due to overfishing and ecological changes, but the species remains a vital component of Pontic marine biodiversity.