CSIRO’s new DNA test for ageing fish could support conservation

By Shannon Jenkins

Thursday June 24, 2021


The CSIRO has developed a non-lethal DNA test that can improve management of wild fish populations by determining their age.

Prior to the development of the new test, scientists determined the age of fish by counting growth rings in their ear bones, known as otoliths. However, this method could not be conducted on live fish.

The new DNA test is a non-lethal, fast, and cost-effective method, according to Dr Ben Mayne, a postdoctoral fellow with CSIRO’s Environomics Future Science Platform.

Mayne’s team initially worked with zebrafish to develop the DNA test. They then calibrated their technique for three threatened species — Australian lungfish, Murray cod and Mary River cod — using fish of known ages, bomb radiocarbon dating of scales, and ages derived from otoliths.

The test can be adapted for other fish species, and could be used to ‘support conservation projects and sustainable fisheries worldwide’, Mayne noted.

“Knowing the ages of fish in a population is vital for their management, such as setting sustainable harvests or determining whether a species is at risk of extinction as well as understanding growth and reproduction of a species,” he said.

The development is part of CSIRO’s ongoing research into ways to use DNA to measure and monitor the environment, including estimating the lifespan of vertebrate species.

A paper on the research, which has been authored by researchers from CSIRO, Seqwater, the Queensland and NSW governments, the University of Queensland, and the University of Western Australia, has this week been published in Molecular Ecology Resources.

Seqwater’s Dr David T. Roberts, who has been studying lungfish for more than a decade, said the ‘breakthrough’ method would advance understanding of lungfish population dynamics and improve conservation efforts ‘long into the future’.

Queensland Department of Regional Development, Manufacturing and Water employee Tom Espinoza also weighed in on the benefits of the new test.

“Australian lungfish, Murray cod and Mary River cod are iconic species in Australia due to their economic, scientific and cultural value,” he said.

“Non-lethal ageing provides an important platform from which to develop this technique across more species and improve management of the fisheries and natural resources that support them.”

READ MORE: Don’t count your fish before they hatch: experts react to plans to release 2 million fish into the Murray Darling


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