Barramundi is a protandrous hermaphrodite. Males mature at about four years of age and change sex at about seven years (85–100 cm TL (Total Length)), becoming functional females (Moore, 1979). Some primary females may be present (Moore, 1980). L. calcarifer is a catadromous fish, inhabiting rivers before returning to estuaries to spawn. Spawning occurs in brackish water and larvae (1.5 mm) passively drift into coastal swamps.
Juveniles migrate upstream and sub-adult fish remain in freshwater until they reach sexual maturity. Maturing males migrate downstream during the spawning season (Russel and Rimmer, 2004) (see Figure 2).
