The Richmond River cod was a form of '' Maccullochella'' cod, now believed to have been eastern freshwater cod, ''Maccullochella ikei'', that occurred naturally in the

Richmond River The Richmond River is a river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may ...

system, an east coast river system in north-east

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. Eastern freshwater cod in turn are a species of ''Maccullochella'' cod found in east coast drainages and originating from

Murray cod The Murray cod (''Maccullochella peelii'') is a large Australian predatory freshwater fish of the genus '' Maccullochella'' in the family Percichthyidae.Dianne J. Bray & Vanessa J. Thompson (2011Murray Cod, Maccullochella peelii Fishes of Au ...

, ''Maccullochella peelii'', that crossed the

Great Dividing Range The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills. It runs roughl ...

and entered east coast drainages from a river capture event between 0.62 and 1.62 million years ago (mean estimate 1.1 million years ago). Richmond River cod are extinct, from

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

including gross

siltation Siltation is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary o ...

, and whole-of-catchment scale bushfires and

fish kill The term fish kill, known also as fish die-off, refers to a localized mass mortality event, mass die-off of fish populations which may also be associated with more generalized mortality of aquatic life.University of Florida. Gainesville, FL (200 ...

s in the 1930s. The Richmond River system has now been restocked with small numbers of eastern freshwater cod from the Clarence River system, but these appear to have been insufficient to re-establish populations; there is no evidence of these stocked fish reproducing.

References

Further reading