Document ID: chunk:federal_register_of_legislation:F2024L00270:body:0:p34
Version: federal_register_of_legislation:F2024L00270
Segment Type: other
Provision Reference: 
Character Range: 92954–95955

any broader conservation management strategy. With no designated outlet for young bred in captivity, adults were segregated to reduce breeding and the captive population ultimately aged and declined (Harley and Lowry 2013; Steventon et al. In review).
In 2012, Zoos Victoria, initiated a new captive breeding program for Leadbeater's possum to provide insurance against the extinction of the last lowland population, and a future source of animals to re-populate restored habitat in Yellingbo and at least two additional populations. To minimise impacts on the wild population, the collection of founders for captive-breeding was restricted to 3–6 individuals per year (Harley 2015a). The initial target for the size of the captive-breeding program for lowland Leadbeater's possum was 12 pairs, and 21 founders were collected. None of these founders successfully produced young, prompting several reviews of captive husbandry and diet. The causes for the failure are unclear, however male infertility has been considered a likely cause. The captive diet is likely to be a contributing factor, and in 2018 and 2019, the captive diet at Healesville Sanctuary was refined under the guidance of Dr Michelle Shaw, Wildlife Nutritionist at Taronga Zoo. Given that highland Leadbeater's possums have previously bred in captivity at many institutions, in 2019 two highland colonies were brought into captivity to test the new diet and husbandry regime. To date, three litters have been produced by these highland colonies, however the rate of production remains lower than would be expected (D. Harley, pers. comm.). Healesville Sanctuary have also housed several mixed highland-lowland pairings to examine compatibility as part of the genetic rescue programme aiming to alleviate inbreeding in the lowland population (Zilko et al. 2021). No outbred young have been produced to date.
In 2023, the captive population at Healesville Sanctuary contains 6 lowland and 11 highland Leadbeater's possums. Current priorities for the captive-breeding programme include 'ranching' or temporary holding in captivity of lowland subadults sourced from the wild from Yellingbo in order to establish new pairs for translocation, and further examination of the compatibility of mixed highland-lowland pairings to support gene-pool mixing (D. Harley, pers. comm.).
A major investigation of Leadbeater's possum health, predominantly focused on the captive population, has recently been completed by Dr Chloe Steventon. This study collated data for highland and lowland possums held in captivity between 1970 and 2021 (Steventon et al. 2022, In review). Of highland possums 39% of females and 37% of males bred successfully. Reproductive contributions were highly skewed, with 11 females and 12 males producing 75% and 80% of all offspring, respectively (Steventon et al. In review). The median longevity of possums held in captivity was 5.01 years for highland individuals and 5.61 years for lowland individuals. In addition to