Biology

Commonly found in coastal waters, the star sturgeon spends the day close to the seabed, where its downward-facing mouth helps it to feed on bottom-dwelling organisms, such as worms, molluscs and small fish (2) (4). At night, the star sturgeon becomes more active, rising up to the water surface to find other sources of prey (4). In order to reproduce, the star sturgeon must undergo a migration from the sea into a freshwater river, swimming upstream to the spawning ground. Interestingly, there are two separate “races” of star sturgeon, which display different spawning behaviours. One race migrates and spawns during spring and summer, while the other migrates in the winter, over-winters in the river and spawns in the following spring (2). A single female produces a vast amount of eggs, in the order of hundreds of thousands, which stick to river vegetation and stones (6). Generally, it is only the juvenile star sturgeons that are threatened by predation, as the large size and armour of the adults helps to deter predators (2) (6). Nevertheless, on occasion, the parasitic, eel-like lamprey has been known to cause fatal injuries to adult star sturgeons (6).