THE DNA of freshwater fish in the Murray-Darling Basin has given scientists important clues to which species may have natural resilience against climate change in one of Australia’s most ecologically and economically important wetland habitats.

The golden perch, also known as the ‘yellowbelly’, has been identified by Flinders University ecologists as being ‘genetically wired’ to cope with future environmental change due to the harshness and unpredictability of its native habitat.

“In many cases, the rate of environmental damage to our wetland ecosystems is exceeding evolution, however we now believe that those fish populations like the golden perch that already occupy extreme habitats have a high resilience to environmental change due to their DNA make-up,” says Dr Catherine Attard, Lecturer in Molecular Ecology at Flinders University.

“By analysing the genetic variation of golden perch populations in the Murray-Darling Basin, we have indeed been able to show that environmental variability is a driving force in genetic diversity and natural selection and may help future-proof the species in an increasingly human-modified world.

“The survivabilty of the golden perch is aided by the fact that this fish species can traverse thousands of kilometres and brood in a number of different habitats along the Murray-Darling flow line, enabling it to distribute its genetic diversity,” Dr Attard says.

In contrast, the research team has also shown that another freshwater fish in the Murray-Darling Basin, the threatened southern pygmy perch, is less likely to cope with climate change.

“We have seen that the southern pygmy perch and many other small native fish in the Murray-Darling are incapable of moving long distances.

“Their populations have become fragmented and so, even if they were genetically resilient to environmental change, their diversity cannot currently spread to newly-altered habitats,” says Dr Attard.

Currently the Murray-Darling Basin is home to 46 species of native fish which have been reduced to 10 per cent of their pre-colonisation population levels due to the loss and degradation of habitat.

Australia’s Native Fish Strategy for the Murray-Darling Basin aims to rehabilitate native fish communities back to 60 per cent of their pre colonisation levels by 2050.

“Biodiversity is the key to achieving the ambitious agenda of the Native Fish Strategy because it underpins all life,” says Dr Attard.

“Without biodiversity there is no sustainable food chain, no water purity, no clean air, and no healthy ecosystems.

“Given that climate change is expected to increase aridity across our river systems and further alternative habitats, there has never been a better time to study the genetic resilience of our native species and use this information to fortify our aquatic wilderness,” Dr Attard says.

02/02/2018