Population trend of feral camels in the Northern Territory, Australia

We conducted a broad-scale aerial survey between 20 August and 12 October 2001 to ascertain the distribution and abundance of feral camels in the southern part of the Northern Territory. There was a minimum of 80 533 feral camels in the Northern Territory at the time of the survey. This figure is corrected for perception bias (a result of observers missing animals that are potentially visible), but not for availability bias (a result of some animals being concealed from the observers). The population of feral camels in the Northern Territory increased at a mean annual exponential rate, r, of 0.093 between 1993 and 2001. This represents an increase of ~10% per year or an approximate doubling in population size every 8 years. This trend is likely to continue for the foreseeable future. We use the results of an earlier survey (which included the Northern Territory, South Australia and Western Australia) to give a minimum figure of 300 000 feral camels for Australia in 2001. We discuss what is known of the impacts of feral camels in Australia, the inadequacy of current management practices and issues to be considered in designing an effective long-term management strategy for the species.