4 days ago
Feral pig cull reduces pest numbers in WA's Northern Agricultural Region
A six-month cull has removed a "surprisingly large" number of feral pigs from Western Australia's Midwest landscape.
WARNING: This article contains an image some readers might find distressing.
Experts say the record results demonstrate how quickly the declared pests can spread.
Feral pigs are estimated to cause $156 million of damage to Australian agricultural production each year, and can carry diseases and damage the environment.
On-ground shooters and aerial pest controllers working from helicopters trapped, baited or shot 11,800 pigs across a 550,000-hectare land area near Geraldton, known as the Northern Agricultural Region (NAR), as part of the cull.
The region is a known hotspot for the pest, but the number of pigs removed has shocked organisers and farmers.
National feral pig management coordinator Heather Channon said a series of favourable seasons had allowed pigs to breed in large numbers in some parts of Australia, such as the NAR, and it was difficult to estimate their population or geographical spread.
"It's a tremendous amount of pigs that have come out, one of the bigger numbers that I've seen in that region, but it doesn't mean that we've got them all," she said.
"That's where we have to be really careful. While we've got a big number, we don't know what the starting number was."
Pigs can have at least two litters every 12 months, and litters can range between four and 12 piglets, a breeding efficiency Dr Channon said "allows the problem to quickly exacerbate".
She said that with feral pig populations expanding across Australia, landowners often did not know if pigs were present.
"It's been estimated that around 45 per cent of Australia's land mass is affected by feral pigs. They're resilient and adaptive animals able to live in dry conditions and in mountains."
Dr Channon said pigs were "clever" adversaries as they quickly learnt how to avoid control attempts.
Managing feral pigs has been an ongoing and costly battle for grain and livestock farmer Scott Bridgeman, who farms near Northampton, 50 kilometres north of Geraldton.
He said pigs reduced crop yields, either by running their nose along furrows to eat seeds after they had been sown, or by eating mature grain crops before harvest.
"It's quite distressing when you come back there and there's no plants, then the country blows away," he said.
"They're a real pest."
Mr Bridgeman said the pigs nested in flowering canola, flattening the plants and eating canola flowers before moving on to eat wheat when it was ripe.
He said some farmers had begun building exclusion fences to keep out the large numbers of kangaroos and pigs moving from bushland into crops.
"You're probably looking at $6,000 to $8,000 a kilometre [to build fencing] ... but when you have a high pest burden, it's definitely worth it," he said.
Mr Bridgeman said pigs were shot on his property this year, but they were an ongoing challenge.
Clare Engelke, who coordinates the biosecurity group responsible for feral pig control in the NAR, said most pigs were removed by aerial shooters.
She said it was the most effective way to humanely remove large numbers, but continuous on-ground control by landholders was essential to prevent the population exploding again.
"We knew there were lots of pigs, but the number surprised us, and they were in areas we didn't expect them at all," she said.
"It's not just about protecting livelihoods and crop production, it's about the environment in terms of water quality and protecting remnant vegetation.
"They impact native species and biodiversity ... it's a bigger problem than crop protection."
Dr Engelke said the Northern Biosecurity Group could help landowners with feral pig control, and she encouraged people to join the free service.
