NSW mouse plague: Fish feed on mice in major waterways

The mouse plague has hit the water in NSW with fish found to be consuming scores of the rodents, causing them to swell in size.

The mouse plague has hit the water in NSW with fish found to be consuming scores of the rodents, causing them to swell in size.

It appears the mice — which have decimated homes, crops and machinery from Bourke to Wagga Wagga — have taken to water in search of food.

But the predators have turned into prey.

Dubbo fisherman Aaron Graham, 26, has reaped the reward of the plague when dangling a line for Murray cod along the Macquarie River.

“The last few years the cod have been around 40-55cm but now they’re up around 65-80 cm. It would have to be down to the amount of mice they are eating, they’re fat and bloated,” he said.

The mice attempt to swim across the river in search of food but more-often-than not they end up in the gaping mouths of the voracious cod.

The cod have been spewing up mice when caught by fishermen Picture: Supplied

Dubbo fisherman Aaron Graham, 26, has found the fish have swelled in size during the plague.

“Any lure that swims across the surface of the water like a mouse works a treat (when catching the cod),” he said.

“Once the cod are in the boat you can smell the mice before you see them. I had one fish spew up about 10 mice at once. You can see how fat all the cod are, they’re full of mice.”

While cod has boomed in size, the same has not happened for one of the mice’s largest predators — snakes.

Snake catcher Harley Jones said the mice plague would not affect the amount of the reptiles.

“It’s winter. They just bunker down, it is very rare for any species to be active at this time,” he said.

“I don’t expect for there to be a boom later in the year. Just because there’s more mice there doesn‘t mean there are more snakes.”

The plague has gotten so bad the state government has brought in a mouse poison so powerful it has been banned for years.

The State Government is sweating on an emergency permit from the Australian Pesticides and Veterinary Medicines Authority to spread grain laced with the lethal bromadiolone around the perimeter of farm paddocks across NSW.

More than 400 farmers have already signed up to use the poison as mouse bait.

The fish are normally between 40-55cm but have swelled to 65-80cm. Picture: Supplied

The barrels of bromadiolone have been gathering dust at a warehouse on Melbourne’s northern outskirts for the past 10 years, since it was banned from widespread use in paddocks because it is also lethal to mouse-eating predators such as snakes, eagles and owls.

The Daily Telegraph understands the government has rationalised the use of the poison as the plague is getting so bad it is impacting other native species.

There are concerns the poison will impact the soil quality, water basin and kill other animals.

Healthy Rivers Dubbo spokeswoman Melissa Gray said local species will struggle if the poison is ‘napalmed’.

“Everything is connected to everything else. If we are not willing to accept that napalming one part of the environment will alter the others it is wrong,” she said.

“We have already lost 90 per cent of the native fish in the area in the last 140 years. Now we’re going to turn around and napalm the vulnerable Murray cod.”