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The management of overabundant marsupial populations in Australia presents wildlife managers with numerous challenges. The prevailing socio-political climate is such that lethal control techniques are often deemed unacceptable for these populations, particularly in the case of Koalas Phascolarctos cinereus. Fertility control has been heralded as a future panacea for these problems, but after a decade of investigations, where are we? Large sterilisation programs have been the cornerstone of many koala management programs in Southern Australia to date, but evaluation of these programs has been limited. Advances have been made in the development of protocols for the treatment of individual animals with progestin and gonadotrophin-releasing hormone (GnRH) agonist contraceptive implants or via surgical sterilisation, but their large-scale effectiveness has not yet been clearly demonstrated. This paper reviews the literature on overabundant marsupial populations, with specific reference to management issues related to overabundant koala and macropod populations. The emerging fertility control technologies, in the form of long-acting contraceptive implants, are discussed along with details of ongoing trials designed to evaluate their effectiveness. This information is used to determine recommendations for developing and implementing management plans for overabundant marsupial populations.

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