Catfish reveal taste for mice
A cat’s penchant for mice is well known, but it seems the little rodents are also not safe from its aquatic namesake in Pilbara waters.
Murdoch University researchers have discovered the lesser salmon catfish of the Ashburton River near Onslow is eating native mice when available.
It was thought the diets of catfish consisted primarily of insects, crustaceans and plants, but stomach examinations revealed SOME had consumed native spinifex hopping mice.
Murdoch Centre for Fish and Fisheries lead researcher Erin Kelly said it was likely the catfish were gaining access to the mice opportunistically.
“Dryland rivers experience extreme cycles of drought and flooding, which leads to a great variation in the type and amount of food available at certain times,” she said.
Ms Kelly said the spinifex hopping mouse dug deep burrows in the sand of riverbanks that could flood and collapse, allowing the catfish to take advantage. “Population booms are also reported for the spinifex hopping mouse, often within three to 10 months after periods of rainfall,” she said.
“The fish we collected for this study were caught during the early dry season — a time of expected population growth for this mouse species.
“Both species are nocturnal, and it is also possible that the catfish are actively hunting mice on the riverbank.”
Ms Kelly and her co-researchers caught 18 lesser salmon catfish from the Ashburton River, and found the small mammals at various stages of digestion within the stomachs of eight of the fish.
Mammals have been infrequently reported in the diets of Australian catfish and other native northern Australian fish species such as the mouth almighty, but this is the first report of high levels of terrestrial mammal consumption by any Australian catfish.
Ms Kelly said understanding the links between aquatic and terrestrial food webs was vital to our understanding and conservation of river and riverbank ecosystems.
The Ashburton River catfish will eat native mice.