Sturgeon

Presentation

Sturgeon is a primitive bony fish belonging to the Acipenseridae family, which appeared more than 200 million years ago. Its elongated body is covered in rows of bony plates called scutes rather than conventional scales. This anadromous or freshwater fish lives in rivers, estuaries and temperate seas of the northern hemisphere. It is best known for its eggs, marketed as caviar, which has led to intense overfishing of many species. Several species of Sturgeons are now among the most endangered fish in the world.

Sturgeon has an elongated fusiform body protected by five rows of bony scutes. Its head has a pointed rostrum and a protractile mouth devoid of teeth, preceded by four sensory barbels. Its skeleton is largely cartilaginous, a trait inherited from its ancestors. Color varies from gray-brown to black on the back, with a lighter belly.

Characteristics

Indicative values: they vary by subspecies, sex and region.

Habitat and distribution

Sturgeon frequents large rivers, estuaries and coastal areas of temperate seas, as well as certain lakes for strictly freshwater species. It favors fresh, well-oxygenated waters, with sandy or gravelly bottoms suitable for feeding and reproduction. Some species spend most of their adult lives at sea before moving up rivers to spawn.

Behaviour

The Sturgeon is a generally solitary fish with rather slow habits, active especially at dusk and at night. Many species are migratory, going up rivers to reproduce after spending part of their lives at sea or in brackish waters. It can live a very long time and reach sexual maturity late, sometimes after ten years. This behavior makes it particularly vulnerable to disturbances in its habitat.

Reproduction

Reproduction takes place in spring or summer, when adults move upstream towards spawning grounds with gravelly bottoms and fast currents. The female lays several hundred thousand to a few million eggs which are externally fertilized by the male. Sexual maturity is late, reached between 8 and 20 years depending on the species, and females often only reproduce every two to four years. This reproductive slowness strongly limits the recovery capacity of overexploited populations.

Peculiarities

Sturgeon is famous for its eggs made into caviar, one of the most prized and expensive food products in the world. Some species, such as the beluga whale, are among the largest freshwater fish ever recorded. Its cartilaginous skeleton and bony scutes make it a living vestige of very ancient fish lineages.

Threats and conservation

Overfishing linked to caviar production has significantly reduced wild populations of Sturgeons. The construction of dams blocks access to historic spawning grounds and fragments the habitats necessary for reproduction. The pollution of rivers and the degradation of wetlands further aggravate the decline of many species. Several species of Sturgeons are now considered among the most endangered in the world.

References

Profile updated 23 August 2026 · Reviewed by the TunisieVet editorial team.