Sawfish use their long serrated noses to find and dismember hapless fish, an Australian researcher has discovered, debunking a previous assumption that the saw was a simple foraging tool.

A sawfish can grow to five metres or more. Its saw is lined with teeth along the sides and is actually a highly sensitive detection organ, the new research shows.

“It is packed with thousands of tiny pore-like organs which can detect the minute electric fields surrounding living organisms, and it can also be used to attack its prey,” said Barbara Wueringer, a researcher from the University of Western Australia and the University of Queensland.

Ms Wueringer, who studied sawfish in Cairns, is a winner of the federal government’s Fresh Science program, which highlights the work of early career scientists.

Her study revealed that sawfish have more of the pore-like organs on the upper side of the saw than their cousins, the shovel-nosed ray. This suggests that sawfish use their saw to detect fish swimming in the space above their serrated noses.

“Northern Australia is considered to be the last stronghold in the world for four species of sawfish but if we do not understand these animals, we will not be able to save them,” she said.

Threats to sawfish include fisherman who trade nose-saws as curios.