The Action Plan for Australian freshwater fishes
R. Wager and P. Jackson
Environment Australia, June 1993
ISBN 0 6421 6818 0
Recovery outlines (continued)
Species recovery outline: Purple Spotted Gudgeon (Murray-Darling stock)
Family: Eleotrididae
Scientific name: Mogurnda adspersa
English names: Purple Spotted Gudgeon, Southern Trout Gudgeon
Stock taxonomic status: Formally described by Castelnau 1878. Recent electrophoretic studies by the South Australian Department of Fisheries indicate that populations from the Murray-Darling Drainage display considerable genetic divergence from east coast stocks, and warrant classification as a separate taxon. East coast stocks also display considerable variation between drainages.
Remnant populations of purple spotted gudgeon from the Murray-Darling Drainage are all similar electrophoretically. Based on current data, all extant Murray-Darling populations may be treated as components of one stock.
Stock survival status: Has undergone a serious decline in distribution and abundance throughout former habitat. Declared extinct in South Australia. Presumed extinct in Victoria. Known remnant populations are restricted to southern Queensland and northern New South Wales.
- Action plan status: Endangered.
- Australian Society for Fish Biology status: Restricted (Murray-Darling and east coast stocks are not separately listed).
- Proposed new IUCN criteria status: Critical, (inferred habitat destruction).
Former distribution: Common throughout the entire Murray-Darling Drainage system and the River Torrens and Onkaparinga River in South Australia. Regularly used as live bait for Murray cod (Maccullochella peelii) pre-1940.
Current distribution: Patchily distributed in a few streams in the region of the Queensland/New South Wales border. Recorded recently from the Dumaresq Condamine, MacIntyre, and Severn River Systems.
Habitat: Usually associated with benthic structure in water up to two metres deep. May be associated with rocks, snags or aquatic vegetation at different sites. Current populations are correlated with low turbidity.
Reasons for decline: Unknown. Occurrence is inversely correlated with presence of gambusia (Gambusia holbrooki). Abundance of populations has been observed to decline as gambusia invade habitat and become more common, although due to lack of sampling occasions results are inconclusive. Significance of other factors (abiotic parameters, other introduced species, flow regulation) are being investigated through a multivariate outplanting experiment to relate persistence to particular habitat variables.
Conservation reserves on which species occurs: Numerous reserves throughout the Murray-Darling system. However, these offer little protection to instream habitat, or protection from upstream influences, or protection from capture. Conservation reserves are currently irrelevant to preservation of this stock.
Other public lands on which species occurs: Several, but comments as above apply.
Other land on which species occurs: Various private lands, generally used for agriculture.
Is knowledge about stock adequate for objectives and actions to be defined accurately? (If not provide list of additional studies required): No.
- Determine the taxonomic status of purple spotted gudgeons.
- Determine environmental requirements
- Determine impacts of introduced species.
Recovery objectives:
- Define taxonomic status and genetic stocks of purple spotted gudgeon over whole distribution.
- Precisely define current stock distribution.
- Define and mitigate key causal factors resulting in population decline.
- Re-introduce populations to suitable habitat.
- Monitor success of re-introduced populations and refine management accordingly.
Management actions already initiated:
- Definition of genetic stocks is complete and is being written up (South Australian Endangered Fishes Working Group, in cooperation with South Australian Department of Fisheries, South Australian National Parks and Wildlife Service, and the Murray-Darling Basin Commission).
- (15.2) Experimentation is underway to identify critical variables by outplanting fish into diverse habitats and monitoring survival. Identified factors can then be tested under controlled conditions and by outplanting into predicted 'acceptable' conditions. Preliminary correlations between known residual populations and habitat variables have been completed preparatory to this work (South Australian Endangered Fishes Working Group, in cooperation with South Australian Department of Fisheries, South Australian National Parks and Wildlife Service, and the Murray-Darling Basin Commission).
Management actions required: These have not been adequately defined.
- Declaration of additional conservation reserves: Yes.
- Possibly of value for preservation of key tributary habitat, but this must be linked to integrated catchment management schemes to ensure in-stream habitat protection.
- Habitat management:
- Depends on the results of 15.2, and will probably depend on management of private land under integrated catchment schemes.
- Feral animal control:
- Possibly need to identify means of controlling both spread of gambusia (by humans and upstream dispersal) and numbers of gambusia where established.
- Translocation or re-establishment of populations:
- Re-introduction of populations into suitable habitat will eventually be necessary, but should be minimised to allow natural establishment.
- Captive breeding:
- Essential to completion of 15.2 in South Australia as this species is extinct in that State. Captive populations should be managed to maintain maximum genetic diversity.
- Other: Yes.
- As the above objectives are completed, the successes will be presented to the public to increase their awareness of freshwater issues, the need for action and what can be done. Where possible, land holders and private individuals will be used to complete establishment actions.
Organisations responsible for conservation of stock:
- South Australian Department of Fisheries.
- New South Wales Division of Fisheries.
- Queensland Department of Primary Industries.
- Victorian Department of Conservation and Natural Resources.
Other organisations or individuals involved:
- South Australian Fishes Working Group.
- South Australian National Parks and Wildlife Service.
- Murray-Darling Basin Commission.
- Australia New Guinea Fishes Association.
- Native Fishes Group, South Australian Aquarium Society.
Can recovery plan be carried out with existing resources?: No.
The current Recovery Outline is entirely volunteer based with advice and experimental design provided by South Australian Department of Fisheries, research staff. Funds for electrophoretic analysis have been made available from the Murray-Darling Basin Commission. Additional funds are required.
- To complete the investigation on the effects of critical environmental variables requires operating funds of $5 000.
- Subsequent funding requirements for habitat improvement and re-introduction of populations will be determined on completion of 15.2.
- Annual monitoring for remnant Queensland and New South Wales populations of this stock will require one biologist and one technician for two weeks – $2 820, plus car hire and camping allowance – $1 200.
Total: $5 000
Annual monitoring: $2 000
Remarks:
- Determination of recent distribution done by Peter Unmack and Rob Wager.