Koala sperm banks can future-proof populations

By Candice Marshall

Apr 13, 2022

Researchers propose that a frozen koala sperm ‘biobank’ is the best long-term solution – and the most cost-effective way – to save Australia’s iconic koala.

Biobanking and adapting existing assisted reproduction technology already being used to help people conceive are important tools needed to future-proof koala populations, according to a unique model developed by researchers at the University of Newcastle.

Authors of the model, published in international magazine animalsargue that the development of these tools can help existing captive breeding programs to preserve genetic diversity, avoiding the current problem of inbreeding.

“Our modeling shows that replenishing frozen founder sperm in koala colonies using various assisted reproductive technologies — such as those common in agriculture and human fertility — could significantly reduce inbreeding and allow captive programs to maintain smaller colonies while maintaining them. yet meet optimal genetic diversity targets,” said lead author and Honorary Associate Lecturer at Newcastle University, Dr. Lachlan Howell.

Using frozen sperm can also help wild populations, explains Dr. Howell explains, “We can reintroduce genetic variation in wild koala populations without displacing koalas.”

Financial advantages

While existing captive breeding programs for koalas have been incredibly successful, they face limitations when it comes to not only genetic diversity, but also high costs.

Co-author and postdoctoral researcher in the School of Environmental and Life Sciences at Newcastle University, Dr. Ryan Witt, says their model shows a 5-12 fold reduction in the total program cost of current captive koala breeding programs.

“Captive breeding programs require larger koala colonies to avoid inbreeding. But by integrating assisted reproduction, we can reduce the number of koalas that need to be kept in captivity, lower costs and improve genetic diversity,” says Dr Witt.

“This would free up valuable conservation funding to support a wider range of species, or to support other koala conservation efforts, such as habitat restoration.”

Dr Ryan Witt (left) and Dr Lachlan Howell with a koala
(Phascolarctos cinereus) at Port Stephens Koala Hospital, NSW. Image Credit: University of Newcastle

‘We have to do something’

In February of this year, koala populations in Queensland, New South Wales and the Australian Capital Territory were officially classified as endangered.

Without intervention, koalas are predicted to become extinct in New South Wales by 2050.

“They are in constant danger,” says Dr. Witt.

“We’re now at a point where we need to do something to manage the koalas in the future to make sure we still have koalas here 30 years from now… koalas need all the help they can get.”

dr. Howell agrees, adding, “We have no insurance against drastic population decline.

An example of a drastic population decline came with the 2019-20 wildfires.

“What we saw was thousands of koalas being wiped out. Conventional captive breeding programs just can’t keep up with that drastic loss – we don’t have an insurance policy that is cost-effective and financially viable to reduce this – so we want to develop tools that will allow the frozen storage of what is essentially insurance against these drastic losses,” says Dr Howell.

koala paul Related: Our koalas: recovery from wildfires and challenges ahead

What now?

“We know that artificial insemination with fresh and chilled sperm works in koalas,” says Dr. Howell. “The hurdle is trying to freeze sperm and make use of it.”

“All it takes now is more research and funding to adapt existing assisted reproduction technologies so that we can cryopreserve koala sperm just like we do in humans.”

What is really needed is a cash injection, says Dr. Witt.

“We essentially have all the infrastructure we need to start building this technology.

“All we really need is an injection of funding to do the research to get this technology up and running and moving in the right direction so that we’re in 10 or 20 years and can be integrated into a wider network.”

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