Fish frequenting littoral zone, it lives the major part of his live in sea but enters rivers for reproduction. At the sea, it occur in coastal and estuarine zones on soft bottom. In freshwaters, it inhabits estuaries and large rivers. Juveniles are found both in estuaries and in the sea. Usually solitary. Feeds on crustaceans, mollusks, polychaete worms and small fishes. A long-lived and slow-growing species. Reaches 500-600 cm and maybe live up to 100 years. Sexually mature at an age of 7-9 years. Females produce 800,000-2,400,000 sticky dark grey eggs which adhere to the stones. Utilized fresh and frozen, and also for caviar; eaten steamed, pan-fried, broiled, boiled, microwaved and baked. A threatened species, mainly due to bycatch, poaching, habitat degradation and physical obstacles to migration.
Eastern Atlantic: North and White Seas, European coasts of Atlantic, northern Mediterranean eastward to Rhodos, western and southern Black Sea, Occasionally recorded from Iceland, Morocco and Algeria. In most large rivers, but not recorded from Danube upriver of delta. Today restricted to Garonne drainage in France.