Occurs in the sea close to shore and estuaries, not entering pure marine waters. In freshwater, it inhabits large deep rivers (Ref. 59043). A long-lived species which is found mainly over sand and mud. Feeds on bottom-living invertebrates and small fishes. Reproduction takes place from May to July. Is threatened by habitat destruction, pollution and overfishing (Ref. 26100). The flesh is used for food but the eggs are not consumed as caviar (Ref. 6866).