R. Wager and P. Jackson
Environment Australia, June 1993
ISBN 0 6421 6818 0
Approximately 195 freshwater species and subspecies have been formally described from Australian waters. A further 22 undescribed taxa are currently recognised. Approximately 8% of Australian freshwater fishes are threatened with extinction, and about 25% are considered to have either significantly declined in distribution, or occur in restricted areas. Although no fish species are known to have become extinct since European settlement, one species has become extinct in the wild.
Habitat degradation and/or interactions with introduced fishes appear to be the major causes of declining fish populations. Many processes threaten habitat and are often interlinked. They include changes to natural flow regimes, clearing of catchment vegetation (particularly riparian vegetation), increased sediment loads, alteration of river bed and banks (including desnagging), reduced water quality and artificial barriers to fish movement. Brown trout (Salmo trutta) and gambusia (Gambusia holbrooki) appear to be the introduced species of most threat to native fishes at present.
The majority of the species listed in this Action Plan occur in south eastern Australia. Whilst this may reflect the areas of most severe habitat degradation, it may also reflect the lack of adequate survey work in other areas of Australia.
The major factor limiting development of adequate Species Recovery Outlines for threatened fishes remains the lack of biological data, particularly relating to habitat requirements. There is a requirement for Federal, State and Territory Governments to make long term commitments to monitor fish populations and to undertake the necessary long term recovery action to conserve threatened species.
This Action Plan provides Recovery Outlines for 24 freshwater fishes and estimates that a total expenditure of $3 700 000 is required to carry out actions recommended in these outlines.
This Action Plan recommends that the Australian Society for Fish Biology (ASFB) Threatened Fishes List form the basis for all other conservation status listings for fish. As the ASFB listing is updated annually, and a number of research activities related to freshwater fishes are presently underway, it is recommended that this Action Plan be reviewed after five years.