- Beluga sturgeon, Huso huso
- 2.4 metre(s)
- Not Applicable ()
Anadromous fish are those that are born in freshwater, migrate to the sea as juveniles then return to freshwater to spawn. The largest species to follow this lifestyle is the beluga sturgeon (Huso huso) which averages 2.2–2.4 metres (7 feet 2 inches–7 feet 10 inches) long and 65–130 kilograms (143–286 pounds) in weight. However, there are reports of individuals exceeding 5 metres (16 feet) and one superlative female, collected in 1827 in the Volga estuary, that was 1,474 kilograms (3,249 pounds) and 7.3 metres (24 feet) long. Beluga sturgeon are currently found in the Black Sea (breeding in the Danube River), the Caspian Sea (breeding in the Ural River) and the Azov Sea (breeding in the Volga River).
Other examples of anadromous fish include certain species of salmon, whitebait, shad, stickleback and trout.
The opposite of anadromous is catadromous, whereby a fish is born in saltwater, spends most of its life in freshwater, then returns to the sea to reproduce. Many freshwater eel species are catadromous.