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: Dwarf Galaxias, Eastern Little Galaxias
Family: Galaxiidae
Scientific name: Galaxiella pusilla
English names: Dwarf Galaxias, Eastern Little Galaxias
Species taxonomic status: Formally described by Mack, 1936.
Species survival status:
- Action plan status: Vulnerable.
- Australian Society for Fish Biology status: Potentially Threatened.
- Proposed new IUCN criteria status: Vulnerable (habitat alteration).
Former distribution: Widespread from Gippsland (east Victoria) to 'Drain L' (south east South Australia). Also in north east Tasmania and Flinders Island, Bass Strait.
Current distribution: Limited to north east Tasmania, Flinders Island, Victoria and South Australia. In Victoria major populations are found in the Grampians and at four sites around Melbourne; Dandenong Creek, Diamond Creek, Cardinia Creek and Balcome Creek. South Australian populations are found in most drains in the south east of the State, including sheltered estuarine situations. Populations are known to experience annual cycles, appearing to be absent from some areas at certain times.
Habitat: Usually in slow flowing waters such as swamps and drains, or backwaters of Creeks and streams; often amongst aquatic vegetation in shallow water. In large pools or lakes usually amongst marginal vegetation. Occasionally found in temporary waters which partially or completely dry in summer.
Reasons for decline:
- Primarily due to destruction of habitat:
- Drainage of large areas of swamps in Victoria and Tasmania.
- Channelisation and removal of aquatic and riparian vegetation.
- Interactions with introduced species:
- Aggression from and predation by gambusia (Gambusia holbrooki). Other introduced species may be implicated in the decline:
- Predation by redfin (Perca fluviatilis) is possible.
- Possible that large carp (Cyprinus carpio) populations may destroy aquatic vegetation.
Conservation reserves on which species occurs: Grampians National Park, (Vic) however, see comment under Remarks.
Other public lands on which species occurs: Land controlled by Melbourne Water (Vic).
Other land on which species occurs: Private land.
Is knowledge about species adequate for objectives and actions to be defined accurately? (If not provide list of Additional studies required): Yes.
Recovery objectives:
- Protect existing populations and habitat.
Management actions already initiated:
- Victorian distribution substantially documented.
- Listed under Schedule Two of the Flora and Fauna Guarantee Act (Victoria).
- Wetlands drainage and destruction has been reduced under the Victorian Wetlands Conservation Strategy.
- Dandenong Creek population is being enhanced by the construction of a new wetland. Gambusia are currently very common in this new wetland.
- Captive populations (including extinct Barwon River stock) being maintained by N. Romanowski.
Management actions required:
- Declaration of additional conservation reserves: Yes. Protect other populations.
- Habitat management: Yes. Native riparian and aquatic vegetation needs to be maintained.
- Feral animal control: Yes. If feasible, reduction or elimination of gambusia, carp and redfin in all populations would be beneficial.
- Translocation or re-establishment of populations: Concentrate on habitat protection. New populations could be established at reclaimed sites around Melbourne.
- Captive breeding: Not yet required.
- Other: No.
17. Organisations responsible for conservation of species:
- Victorian Department of Conservation and Natural Resources.
- Inland Fisheries Commission, Tasmania.
- Fisheries Department, South Australia.
18. Other organisations or individuals involved:
- Paul Humphries, Inland Fisheries Commission, Tasmania.
- Nick Romanowski.
- Peter Unmack.
19. Can recovery plan be carried out with existing resources?: No.
- A full scale survey is required to assess the status of this species in Tasmania. This requires four weeks intensive field work and four weeks to fully document past records, examine past collections, etc. and write-up. Costs must cover a biologist with a technician for field work – $8 260, car hire and camping allowance – $3 400.
- Cost of annual monitoring of this species in Tasmania would be included in an annual program to monitor Swan Galaxias, Clarence Galaxias, swamp galaxias, saddled galaxias and Dwarf Galaxias (see Swan Galaxias for details). Annual funding required for monitoring of this species would be $2 440.
- Cost of annual monitoring in Victoria would include a biologist and technician for four weeks – $5 880, plus car hire and camping allowance ^nd $3 400.
Total: $11 660
Annual monitoring $11 720
Remarks:
- Population numbers can fluctuate widely with changing conditions.
- Humphries (1986) found evidence for drought survival ability. Evidence of aestivation has been obtained by Beck (1986), Peter Breen (Melbourne Water) and Peter Unmack. Peter Unmack is currently monitoring populations for evidence of aestivation.
- Establishment of new populations within former range may require the rehabilitation of suitable wetlands.
- The populations in Grampians National Park may not be secure. At the time the National Park was declared there were existing commitments for the off-stream use of water within the Park boundaries. If these commitments are honoured then further habitat degradation will occur.