Australasian Science: Australia's authority on science since 1938

Sawfish Revealed as the Ultimate Stealth Hunter

The full text of this article can be purchased from Informit.

Researchers from The University of Newcastle have solved a long-standing mystery surrounding the stealth-feeding behaviour of the critically endangered sawfish.

Sawfish are a type of ray found in both salt and fresh water in the Kimberley region of Western Australia. They have a flattened body and a rostrum (snout) lined with razor-like teeth.

Due to their rarity and preference to feed in murky water, sawfish feeding habits have seldom been sighted in the wild. Until now it was widely believed that sawfish sift through silt to uncover their food. The new research, published in The Journal of Fish Biology, described how sawfish detect prey with their rostrum and then swipe rapidly from side to side to impale their kill.

Utilising CT technology, rostra specimens of three sawfish species were scanned to create 3D models. A virtual wind tunnel was then used to imitate their movement in water, revealing that the rostrum’s hydrodynamic shape causes minimal disturbance to the surrounding water.

“The hydrodynamic nature of their rostra makes any movement barely detectable in water,” said lead investigator A/Prof Phil Clausen. “We were surprised at how fast the motion was – our modelling clearly shows that with a lateral swipe, by the time the sword reaches the prey, it’s already too late.

“Our work also shows moving the rostrum a few...

The full text of this article can be purchased from Informit.