Biology

Occurs in brackish waters (20-22 ppt) of coastal lagoons and mouths of rivers and bays (Ref. 4779). Mostly in larger lowland rivers (Ref. 59043). Nerito-pelagic (Ref. 58426). Feeds on small crustaceans, insects, small fishes (Ref. 28219, 28857), worms and clams (Ref. 58426). At sea, feeds on larger crustaceans and small fish (Ref. 59043). No feeding occurs during the upstream migration (Ref. 4779). Lives 10 -12 years, rarely up to 20 (Ref. 59043). Enters rivers in shoals to spawn (Ref. 4779). Spends 6-8 years at sea before maturing and returning to rivers in June - July, to spawn in September - October of same year. A second run in autumn; those fishes remain a year in rivers before spawning. Moves far upstream, sometimes our to 1500 km. Spawns in shallow tributaries with some current in well oxygenated water over gravel bottom. Individual females do not spawn every year; spawns only 2-3 times during entire life. After spawning adults return directly to sea. Embryonic development lasts up to 7 months. Alevins migrate downstream in May - June (Ref. 59043). Collected by fyke nets (Ref. 4526). An important commercial species, but catches and abundance markedly reduced in last years (Ref. 59043).