High survival rate, little breeding success in captive-bred quoll release: research findings

The release of a captive-bred marsupial species has helped to produce some quoll-ity data that will improve the outcomes for next generations. What researchers found.

An eastern quoll on the run. Picture: David Hamilton

A new release of captive-bred eastern quolls has sparked hopes for researchers as they aim to boost the declining wild population in the state.

Researchers from the University of Tasmania, in collaboration with the Tasmanian Land Conservancy, World Wildlife Fund Australia and the Tasmanian Quoll Conservation Program, recently released 24 quolls at The Quoin, a 4,985-hectare property in the Midlands.

UTAS adjunct researcher and a conservation ecologist with the Tasmanian Land Conservancy Dr David Hamilton said the latest release of the captive-bred marsupials into the wild is the second in Tasmania and builds off evidence gathered from the first attempt.

An eastern quoll in its den. Picture: David Hamilton

“We did our release a few years ago at Silver Plains, which is a Tasmanian Land Conservancy property up in the Central Highlands, not too far from Interlaken,” he said.

“That first one was kind of a pilot study to figure out what was going on with releasing quolls into the landscape and then we’re doing a few more over the next couple of years as well in some of these areas where quolls have really seen big dips in population – it’s an ongoing effort.”

Findings from the first release showed that while survival rates were high and the quolls didn’t travel far from the area where they were introduced, they also had little to no breeding success.

A family of eastern quolls. Picture: David Hamilton

This time, a mix of juvenile and adult quolls were released right in the middle of breeding season to avoid this.

“The quolls we released the first time hadn’t actually bred when they were in captivity, which we think may have affected their ability to breed in the wild or to compete with other wild individuals for breeding mating opportunities too,” Dr Hamilton said.

“This time was a mix of juveniles and adults who had bred in captivity too so we’re hoping that they’ll have better breeding success.”

The last breeding release also confirmed a curious event shared between eastern quolls, devils and spotted-tail quolls – multiple paternity in offspring.

“This is females having a litter of up to six young, and they can all have different fathers,” Dr Hamilton said.

An eastern quoll captured by researchers for tracking. Picture: David Hamilton

While planning for another release of captive-bred quolls at the end of the year across one of 14 different sites in Tasmania, Dr Hamilton said the project will continue to compile genetic data from quolls and track the population.

“Every release and in each population, we will keep combining the data to improve on each release and find the factors that make for the best introduction for a quoll population,” he said.

“It’s about finding the ideal conditions to support captive-bred and wild quolls populations for the long-term.”

Originally published as High survival rate, little breeding success in captive-bred quoll release: research findings