Managing Feral Pigs Across Australia

Pigs were first introduced to Australia by early European settlers. Further deliberate releases of domestic animals supplemented by accidental escapes and intentional translocations, have provided the foundations for what has now become an entrenched feral population that requires on-going management. Like every nation, Australia lives with the consequences of past actions and decisions – and where pest animals are concerned, the legacy is a severe one. This article discusses how the management of feral pigs in Australia is conducted against the backdrop of contemporary technical and political considerations, and how control methods are continuing to evolve in order to meet social and practical requirements. Feral pigs in Australia have little physical resemblance to their forebears. Most obviously, the animals are generally uniformly black in colour, although spotted individuals occasionally occur. They also have a relatively lean overall body form with shortened hindquarters and well-developed muscular forequarters. Mature animals commonly have tusks that assist their foraging activities, and that can make them dangerous predators and adversaries if cornered. Feral pigs are numbered in multi-millions in Australia, and occur across almost half of the continent, being particularly abundant in tropical and sub-tropical regions. They occur in every mainland jurisdiction in Australia, raising social and political issues that are further described below. Feral pigs are omnivorous, and will eat carrion as well as plant material, and also kill and consume small animals such as freshwater tortoises, frogs and lambs. The feral pig population poses a multiplicity of problems and concerns for Australia. In one respect, their feeding activities cause direct economic losses to crops, as well as significant ecological impacts on farmlands and nature reserves, where disturbed areas of soil created by their rooting activities are commonly invaded by weeds. They also impact on freshwater ecosystems, where they degrade water quality by wallowing and digging up water plants to eat, placing additional pressure on native fish and frog populations, the latter of which are already being severely impacted by chytrid fungus disease. Feral pigs also carry diseases such as leptospirosis, brucellosis and Q-fever, and are a potential reservoir for other serious animal diseases not currently present in Australia. There is thus a need to establish and maintain integrated management systems and practices to manage this pest population on a continent-wide scale. However, any discussion of the means through which this might be achieved first requires a short detour through the political history of Australia. As with many national matters, the power to legislate and act in the area of pest management reflects the original pattern of British settlement of Australia. Between 1788 and the early 1800s a number of colonies were established as separate political entities on the Australian continent. These colonies united in 1901 as the states of one nation: the Commonwealth of Australia. As part of this process the states ceded responsibility for a number of powers – including the power to manage and regulate matters relating to customs, quarantine and federal lands – to the central national government, but retained a suite of others, including responsibility for functions that have come to include management of pest animals and weeds.