Occur in freshwater to estuarine conditions. Adults breed at sea; juveniles move into estuaries and enter rivers in late winter or early spring. Females remain in freshwater for 7 years, males for 4 years. Return to estuaries before maturing sexually prior to spawning. Oviparous, eggs are pelagic and non-adhesive (Ref. 205). Feed on benthic algae and small invertebrates over muddy bottom (Ref. 6465). Decline in population from obstruction, by dams and weirs, of free passage into rivers.