R. Wager and P. Jackson
Environment Australia, June 1993
ISBN 0 6421 6818 0
Species recovery outline: Lake Eacham Rainbowfish
Scientific name: Melanotaenia eachamensis
English name: Lake Eacham Rainbowfish
Species taxonomic status: Formally described by Allen and Cross, 1982. Recent electrophoretic work (Crowley and Ivantsoff, 1991) indicates that the rainbowfishes from Lake Eacham may be indistinguishable from rainbowfishes recognised as Melanotaenia splendida splendida from other locations on the Atherton Tablelands. However, Ivantsoff and Crowley used small samples and therefore could not assess 'within species' versus 'between species' genetic variation, or the significance of the variation that was observed (J. Hughes, pers. comm.). The current taxonomic status of M. eachamensis is thus uncertain. This Recovery Outline was prepared on the assumption that the rainbowfishes from Lake Eacham are a distinct taxon.
Species survival status:
- Action plan status: Extinct (in the wild).
- Australian Society for Fish Biology status: Endangered.
- Proposed new IUCN criteria status: Critical, (extinct in the wild).
Former distribution: Only known from Lake Eacham on the Atherton Tablelands, north Queensland.
Current distribution: No longer found in Lake Eacham. Captive populations maintained by:
- Queensland Department of Primary Industries' Walkamin Research Station, north Queensland. Large population maintained in an outdoor dam;
- Taronga Park Zoo, Sydney;
- Some members of the Australia New Guinea Fishes Association maintain populations;
- Other private aquarists may maintain small populations.
Habitat: Usually found in clear shallow water at the margins of Lake Eacham, however individuals could be found throughout the surface waters of the Lake. Often observed amongst aquatic vegetation, fallen logs or branches.
Reasons for decline: The decline of rainbowfish numbers in the lake was not quantitatively recorded and as a result causative factors were not conclusively documented. Circumstantial evidence strongly implicates native species illegally translocated to the lake possibly in the early 1980s, particularly the mouth almighty (Glossamia aprion). The banded grunter (Amniataba percoides), archerfish (Toxotes chatareus) and bony bream (Nematolosa erebi) may have also impacted on the rainbowfish population.
Conservation reserves on which species occurs: Formerly in Lake Eacham National Park.
Other public lands on which species occurs: None.
Other land on which species occurs: None.
Is knowledge about species adequate for objectives and actions to be defined accurately? (If not provide list of additional studies required): No.
- Determination of the taxonomic status of M. eachamensis and its relation to the M. splendida group. Electrophoretic analysis of both species is required to determine genetic variation within each species/morph and hence the significance of any variation between the two.
- Determine the taxonomic status of M. eachamensis and its relation to the M. splendida group.
- Determine current status of captive populations and establish formal management plans for these populations.
- Remove all translocated species from Lake Eacham.
- Re-establish the natural fish fauna of Lake Eacham, including the Lake Eacham rainbowfish.
- Educate the public to reduce the likelihood of future introductions to the lake.
Management actions already initiated:
- Captive populations are established and reproducing prolifically.
- Totally unsuccessful restocking of 3000 fishes into Lake Eacham in October 1989.
- Monitoring by J. White (honours student, James Cook University) during 1991 to determine present status of fish populations.
- Preliminary trials being undertaken at Walkamin Research Station to determine the effectiveness of Barramundi (Lates calcarifer) as a predator of the translocated species.
Management actions required:
- Declaration of additional conservation reserves: No.
- Habitat management: Yes.
- Monitor impact of tourists on water quality;
- remove introduced aquatic vegetation.
- Feral animal control: Yes. Remove translocated species, particularly mouth almighty.
- Translocation or re-establishment of populations: No suitable locations found for the establishment of translocated populations. Re-establishment in Lake Eacham dependent on removal of translocated, predatory species.
- Captive breeding:Yes.
- Existing captive populations should be maintained or expanded. A strategy to maintain maximum genetic diversity should be developed.
- Other: Yes.
- Public education into the potential affects of translocated species.
- Monitoring of restocked fishes to gauge survival and population dynamics.
Organisations responsible for conservation of species:
- Queensland Department of Primary Industries.
- Queensland Department of Environment and Heritage.
- Wet Tropics Management Authority.
Other organisations or individuals involved:
- Australia New Guinea Fishes Association.
Can recovery plan be carried out with existing resources?: No.
- Assist existing taxonomic work. Two technicians required for two weeks to collect specimens – $2 400, plus $1 700 for vehicle expenses and camping allowance. Laboratory costs to process specimens – $20 000.
- Annual maintenance of existing captive populations – $5 000.
- Development of a strategy for removal of translocated species requires one biologist and one technician for two years – $147 000, plus operating costs of $15 000 for each year.
- Monitoring to gauge the long term success of restocking would be done by the Queensland Department of Primary Industries.
Annual maintenance: $5 000.
- The Queensland Department of Environment and Heritage proposes to return Lake Eacham to its natural state.
- Allen (in Crowley and Ivantsoff 1991) recommends comparing rainbowfish from Lake Eacham and the Atherton Tablelands with those from coastal regions, as colour and colour pattern differences do exist.
- The Queensland Department of Primary Industries will investigate the value of having this species listed under the Nature Conservation Act 1992.