A bold operation to rescue a tiny, endangered fish species in North Queensland has been declared a success, with populations now thriving in creeks at Australian Wildlife Conservancy (AWC)’s Mount Zero-Taravale Wildlife Sanctuary (Gugu Badhun country). Researchers released over 4,000 rainbowfish into Deception Creek and Puzzle Creek in a last-ditch attempt to save the species, which was at risk of being hybridised out of existence.
The Running River Rainbowfish is a small, freshwater species which lived in a 13-kilometre section of Running River, part of the Burdekin River catchment in north-east Queensland. It’s one of 19 species of rainbowfish, which are found throughout Australian creeks and rivers. This species evolved and survived in isolation, separated from a downstream relative (the more common Eastern Rainbowfish) by a series of gorges and waterfalls that prevented them from mingling.
In 2015, scientists from the University of Canberra’s Institute of Applied Ecology, and the Museum and Art Gallery of the Northern Territory, discovered that Eastern Rainbowfish had been released into the upper reaches of Running River and were interbreeding with the less common species, threatening to wipe it out. It was a race against time for researcher Dr Peter Unmack and his collaborators, who leapt to action to save the species.
“We’re still just getting to understand the diversity of different rainbowfish in some of these Queensland catchments, so when we realised this unique species was under threat in its only habitat, we felt compelled to intervene,” said Dr Unmack.
With snorkels and hand nets, the research team collected rainbowfish from the at-risk populations in Running River. After conducting genetic analysis to make sure they’d caught the target species, a captive breeding program was set up at the University of Canberra and James Cook University. A paper published this month in the international journal Aquatic Conservation documents the project.
The next step was to find a new home where the Running River Rainbowfish could be released. Release sites needed be unoccupied by any other rainbowfish species, and upstream from waterfalls so that Eastern Rainbowfish would not be able to infiltrate the new populations.
The researchers identified two stretches of Deception Creek and Puzzle Creek at AWC’s Mount Zero-Taravale Wildlife Sanctuary which matched these requirements. With support from AWC’s team on the ground, University of Canberra Masters student Karl Moy carried out ten releases of 250 fish at sites on Deception Creek, and four releases of 375 fish each along Puzzle Creek in late 2016 and 2017.
Nearly two years after the introduction, the researchers conducted snorkel transects to monitor the rainbowfish population in the two creeks and found that they were thriving and spreading into the available habitat.
“Saving the Running River Rainbowfish is a really, really big deal,” said Dr Unmack. “It’s only the second example in Australia where a fish has been saved from extinction when it was on the brink of being lost in its only habitat. AWC was instrumental in helping to save the Running River Rainbowfish.”
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