Summary
The Mary River cod (Maccullochella peelii mariensis) is one of Australia's most endangered fish. Natural populations of the species are now restricted to suitable areas of habitat in the Mary River system. Freshwater cod (possibly M. p. mariensis) were also present in the Brisbane-Stanley, Albert-Logan and Coomera Rivers at the time of European settlement. Cod are now considered very rare or extinct in these systems. It is estimated that Mary River cod now occur in less than 30% of their former known range in the Mary River system. Remnant populations may have become isolated from each other due to habitat fragmentation and the impoundment of streams.