Possum biocontrol: prospects for fertility regulation

Research has begun recently into biocontrol of brushtail possums as the only long-term, cost-effective solution to the possum problem in New Zealand, where possums cause significant damage to native forests, threaten populations of native plants and animals, and infect cattle and deer with bovine tuberculosis. Fertility regulation as a means of biocontrol has the support of major animal welfare and conservation groups in New Zealand. Systems are being investigated, mostly in reproduction and development, with the ultimate aim of developing immunologically-based fertility regulation (immunocontraception), but much basic information essential to such an approach for possums is lacking. The key components for the success of this approach--suitable vectors expressing possum-specific reproductive antigens sufficiently to block reproduction--are reviewed. The social and political issues of local, national and international risk and acceptability arising from such an approach are also discussed.