Melanotaenia utcheensis, male, Utchee Creek, South Johnstone R., northeast Queensland, from McGuigan (2001)
The species was previously regarded as being a colour variety of either the Regal Rainbowfish,
M. trifasciata or the Eastern Rainbowfish, M. splendida splendida.
However following mtDNA sequencing (McGuigan et al, 2000) and morphometric analysis (McGuigan 2001)
it was elevated to species status.
Its distribution is limited to the coastal tributaries of the North and South Johnstone Rivers,
and to tributaries of the North Johnstone on the Atherton Tablelands.
These areas have been developed for intensive agriculture - sugarcane and bananas
on the coastal plain and grazing and dairying on the Tablelands.
The natural vegetation was tropical rainforest, but this has been cleared to the
stream banks and worse.
Utchee Creek joining the South Johnstone River
Source: extract from QAP5819028 © DNR 2000
The impacts of this clearing on water quality are :
- increased sunlight onto water and rocks increases water temperature locally and downstream,
upsetting the timing of seasonal events like spawning - a decrease in the amount of leaves and fruits falling into the water
- a decrease in the amount of terrestrial insects falling into the water
- a decrease in the numbers of snags and overhangs on the stream banks,
where small fish find shelter - an increase in sediments from run-off events
- an increase in fertilisers from run-off events
- an increase in pesticides from run-off events
- an increase in spray drift from aerial spraying of bananas
|
It is a sister species to the Lake Eacham Rainbowfish (M. eachamensis), which is listed as an endangered species. This species was originally thought to be present only in Lake Eacham, a small crater lake on the Atherton Tableland, and was considered extinct following the introduction of the native predator fishes Mouth Almighty (Glossamia aprion), Barred Grunter (Amniataba percoides) and Archerfish (Toxotes chatareus). It was later discovered to be present in nearby Lake Euramoo and some local streams, however this shows just how easy its is to lose a species with limited distribution due to the translocation of other fish species. |
 Lake Eacham Rainbowfish, Melanotaenia eachamensis Photo © G. Schmida |
The coastal habitat of M. utcheensis has suffered a similar fate
in that the exotic Tilapia (perhaps 2 species) has been introduced.
This fish is not a predator, but is a very powerful competitor to native fishes.
It is for the above reasons that Mission Beach Environmental Management Group is
in the process of submitting a nomination to both State and Federal Governments that
the Utchee Creek Rainbowfish be added to their respective Endangered Species Lists.
McGuigan et al, 2000: "Phylogenetic relationships and historical biogeography of melanotaeniid
fishes in Australia and new Guinea", McGuigan K.L., Zhu D., Allen G.R. and Moritz C. in Mar. Freshwater Res., 2000, 51, 713-23
McGuigan, 2001: "An addition to the rainbowfish (Melanotaeniidae) fauna of North Queensland", McGuigan K.L. in Memoirs of the Queensland Museum 46(2): 647-655. Brisbane. ISSN 0079-8835.
Dave Kimble April 2005
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