Large catfish are eating mice in a desert river in Western Australia’s Pilbara region, researchers have found.

Murdoch University researchers caught 18 lesser salmon catfish in the Ashburton River and found the native spinifex hopping mice at varying stages of digestion within the stomachs of eight fish.

The research also identified two fish had the remains of three rodents in their stomachs.

It was previously thought the lesser salmon catfish ate insects, crustaceans and plants, but the research reveals the catfish are gaining opportunistic access to the mice.

Lead researcher Erin Kelly from the Centre of Fish and Fisheries Research at Murdoch said the catfish were altering their diets according to what was available, which depended on extreme cycles of drought and flooding that dryland rivers experienced.

“This mouse species has been reported to construct deep burrow systems in the sand of riverbanks,” she said.

“If a burrow of mice is flooded and collapses into the river, the catfish are likely to be taking advantage.”

This is the first report of high levels of terrestrial mammal consumption by any Australian catfish, and learning about the link is vital to understanding river ecosystems in changing climates, Dr Kelly says.

-AAP