Biobanking could save koalas from extinction

Biobanking and assisted reproduction could become a reality for koalas by leveraging the existing technology used to help humans conceive. A newly released model, published in the journal Animals, reveals this would help captive breeding programs to retain genetic diversity, cut the costs required to deliver such programs and help ensure the survival of the species.

“Currently, we have no optimised tools that can store live koala reproductive material, such as sperm, so we have no insurance policy against natural disasters like the 2019–2020 bushfires that threaten to wipe out large numbers of animals at the one time,” said study co-author Dr Ryan Witt, a conservation scientist at The University of Newcastle.

“Biobanking, if developed for the koala, would offer a solution to store or ‘bank’ live koala genetics by freezing sex cells such as sperm. The frozen sperm can then be used to impregnate female koalas in breed-for-release programs, using assisted reproductive technology.”

Witt said the model shows a 5- to 12-fold reduction in overall program costs of current captive koala breeding programs, if biobanking and assisted reproduction are incorporated. While such programs are a powerful tool to save koalas, they face significant challenges including high costs and lack of genetic diversity — the latter of which can lead to reproductive dysfunction and infertility as well as compromising survival, disease resistance and environmental adaptation.

“Captive breeding programs require larger koala colony sizes to prevent inbreeding — but by integrating assisted reproduction we can reduce the number of koalas needing to be in captivity, lower costs and improve genetic diversity,” Witt said.

Through his PhD research at The University of Newcastle, lead author Dr Lachlan Howell spent years developing and analysing this robust model for various endangered animals but believes it offers the koala the most promise.

“The beauty of applying assisted reproductive technologies to the koala population is that … much of the infrastructure is already in place,” Howell said. “We’ve identified 16 wildlife hospitals and zoos across Australia that could act as nodes to collect koala sperm and help integrate assisted reproduction.” Integrating biobanking into the zoo and wildlife hospital network presents a financially feasible model for the uptake of these tools due to the technical and research expertise, captive koala colonies and facilities that already exist across these networks.

“Recent advances have shown us that artificial insemination using fresh and chilled sperm works in koalas,” Howell continued. “The hurdle is trying to freeze sperm and make use of it. All that is needed now is more research and funding to tweak existing assisted reproduction technologies so that we can cryopreserve koala sperm, just like we do for humans.

“By using frozen sperm, we can reintroduce genetic variation into wild koala populations without having to relocate koalas. In NSW, for example, koala populations are declining rapidly in some locations, so they would greatly benefit from the introduction of biobanked material from other unique populations to help manage genetic diversity.”

If cryopreservation is made possible for koalas, it will also open the door to recover and biobank genetic material from koalas who may have died in bushfires or been hit by cars so they can still contribute to reproduction and the population.

Image credit: Penny Harnett/University of Newcastle.

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