The Running River rainbowfish’s dramatic arc

Researchers say they have saved a critically endangered species of rainbowfish from extinction.

The Running River rainbowfish has only been found in a 13km section of Running River in the Burdekin River catchment in north-east Queensland.

So when scientists from the University of Canberra’s Institute of Applied Ecology found the eastern rainbowfish species was interbreeding with the Running River species, they took action.

“We’re still just getting to understand the diversity of different rainbowfish in some of these Queensland catchments,” researcher Dr Peter Unmack says. “So when we realised this unique species was under threat in its only habitat, we felt compelled to intervene.”

In the recent paper, researchers note the discovery of the second less rare species led to the realisation extinction could be on the cards for the rare fish.

“Once eastern rainbowfish had been detected in Running River above the upper gorge in 2015 it was realised that RRR [Running River rainbowfish] was at risk of extinction via hybridisation, as no members of the Australis lineage of rainbowfishes are ever found sympatry,” the paper says.

Sympatry refers to populations of closely related species that occupy the same or an overlapping geographic area without interbreeding.

Unmack and his fellow researchers used snorkels and hand nets to scoop up 52 fish to take back to the University of Canberra, where they determined the species through genetic analysis. This was followed by a captive breeding program at the University of Canberra and James Cook University.

“The only conservation options available for RRR were either to hold the fish in captivity for the long term or to find locations where they could be translocated to, as it would take a massive effort to remove the eastern rainbowfish from upper Running River and then restore RRR in their native range,” the paper says.

“Maintaining the species in wild habitats was the most feasible option, thus the next challenge was to determine whether any suitable sites for translocation might exist.”

The new sites had to be free of rainbowfish species and upstream from waterfalls so eastern rainbowfish would not be in the picture. The research team identified 2 stretches of Deception Creek and Puzzle Creek at Australian Wildlife Conservancy’s (AWC) Mount Zero-Taravale Wildlife Sanctuary in North Queensland that met the brief, and University of Canberra Masters student Karl Moy carried out 10 releases of fish in Deception Creek and 4 releases in Puzzle Creek in late 2016 and 2017, releasing a total of about 4000 fish.

Close to 2 years later, studies found the Running River rainbowfish populations were thriving and spreading.

The paper says the conservation actions have been an “outstanding success” and that the techniques and habitat selection could be used in the rescue of endangered fish in the future.

“Saving the Running River rainbowfish is a really, really big deal,” Unmack says.

“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.”

Earlier this year, Charles Sturt University declared a Snowy Mountains project to rescue the endangered stocky galaxias fish from extinction a success.

The Running River rainbowfish research team’s paper says there have been “very few” freshwater fish extinctions to date.

“… but this is unlikely to remain the case in the future unless appropriate management measures are taken,” it says. “To prevent future declines and extinctions, careful management and continued robust monitoring will be required.”