| 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 up 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 (Ref. 59043). |