Freshwater fish of Australia are limited to approximately 280 species, even though the

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

n continent is larger than the

contiguous United States The contiguous United States (officially the conterminous United States) consists of the 48 adjoining U.S. states and the Federal District of the United States of America. The term excludes the only two non-contiguous states, Alaska and Hawaii ...

. The small scale of species found in Australian inland waters is in some part due to the dry conditions of the continent. Rainfall is sporadic over much of the continent, and fish cannot live in many of the desert regions of South Australia and Western Australia. Most freshwater species are found in tropical or subtropical regions. A large proportion of freshwater species are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to Australia. The family Percicthyidae (temperate perches) and other families suspected in reality to lie within it (e.g. Gadopsidae, Nannopercidae) have risen to prominence in and dominate many of its freshwater systems, in contrast to the Northern Hemisphere where freshwater fish faunas are overwhelmingly dominated by the carp family, Cyprinidae. (No cyprinid species is native to Australia). Due to the illegal introduction of

carp Carp are various species of oily freshwater fish from the family Cyprinidae, a very large group of fish native to Europe and Asia. While carp is consumed in many parts of the world, they are generally considered an invasive species in parts of ...

(''Cyprinus carpio''), Cyprinidae is now present in a destructive form in Australia. The Galaxiidae have become significant in scale in Australia, most of the world's ''Galaxias'' species are found in the continent and neighbouring New Zealand. The Murray-Darling Basin is one significant freshwater system of Australia. It drains approximately 13% of the continent and contains some of Australia's most significant freshwater fish species including the Murray Cod, Australia's largest freshwater fish. Australian freshwater fish have not fared well since European settlement of Australia in 1788. The majority of Australian freshwater fishes are poorly understood and are under threat due to human activities such clearing of riparian vegetation and siltation associated with agricultural practices, snag removal,

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 stock), resulting in t ...

, river regulation through dams and weirs, introduced fish and diseases. Two native fish populations that may have been separate species or sub-species, the

Richmond River cod 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 system, an east coast river system in north-east New South Wales, ...

and the Brisbane River cod, are extinct, and a number of other species are listed as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...

or critically endangered.

References

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External links

Fishes of Australia website

Freshwater FishesFreshwater Fish in Western Australia