Rainbowfish nearing extinction as Lake Kuromoi dries up

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A colourful tropical aquarium fish is approaching extinction following drought and the introduction of an alien fish.

When the ichthyologist Dr Gerald Allen described the rainbowfish Melanotaenia parva from Kuromoi Lake on the Bird's Head Peninsula in West Papua in 1990 he noted at the time that the species was abundant but that the waters were receding.

The water level had already decreased far from the Lake's outlet with the Yakati River, but worse, he also found that a non-native tilapiine cichlid,  Oreochromis mossambicus, had been introduced.

Now a new study by scientists who have just described a new species of rainbowfish from the Bird's Head Peninsula have shown that its home - Lake Kuromoi - is now almost completely dry.

Their observations, which were made in June 2007 but have only just been published, recorded just 1 hectare of water surface remaining and that the Lake was now infested by the introduced tilapia.

Melanotaenia parva has subsequently become "less abundant and very difficult to catch" and now occurs mainly in narrow creeks formed from the dry parts of the lake.

The authors also report that a close relative, Melanotaenia ajamaruensis, may now be restricted to a single remaining locality.

The authors said: "With the objective to promote its ex-situ conservation and to discourage wild catches, we have already started a program of domestication in a governmental aquaculture station located in West Java."