Anadromous (Ref. 5951). The young migrate seaward (Ref. 9043). Epipelagic (Ref. 58426). Spends 18 months at sea after which spawning migration to the natal river or stream occurs; but because the species is less certain of its homing and there is a certain degree of wandering, streams as much as 640 km from natal streams may be used (Ref. 1998, 27547). Upon emerging from the gravel, fry immediately move downstream and remain inshore for a few months before going out to sea (Ref. 27547). Fry may feed on nymphal and larval insects while in fresh water, but may not feed at all. In the sea, young feed on copepods and larvacean tunicates, its diet shifting to amphipods, euphausiids and fishes as the fish grows (Ref. 27547). Other food include ostracods, decapod larvae, cirripeds, tunicates, dipterous insects and planktonic organisms (Ref. 1998, 13434, 27547). Fry may be preyed upon by birds and mammals while adults by marine mammals and large fish (Ref. 1998).