10 ||MAY/JUNE 2017
New Painkiller from Fanged
Fish’s Heroin-Like Venom
A fearless fanged coral reef fish that disables its opponents with
heroin-like venom offers hope for the development of new
painkillers.
The venomous fang blenny is found on the Great Barrier Reef.
“The fish injects other fish with opioid peptides that act like heroin
or morphine, inhibiting pain rather than causing it,” said A/Prof
Bryan Fry of The University of Queensland. “Its venom is chem-
ically unique.
“The venom causes the bitten fish to become slower in move-
ment and dizzy by acting on their opioid receptors,” Fry said. This
meant that the fang blenny was more easily able to escape a predator
or defeat a competitor.
Fang blennies ( Meiacanthus), also known as poison-fang blennies
or sabre-tooth blennies, are popular as ornamental tropical aquarium
fish. “Fang blennies are the most interesting fish I’ve ever studied
and have one of the most intriguing venoms of them all,” Fry said.
“These fish are fascinating in their behaviour. They fearlessly take
on potential predators while also intensively fighting for spacewith similar-sized fish. Their secret weapons are two large grooved
teeth on the lower jaw that are linked to venom glands.
“This study is an excellent example of why we need to protect
nature,” Fry said. “If we lose the Great Barrier Reef, we will lose
animals like the fang blenny and its unique venom that could be
the source of the next blockbuster painkilling drug.”
The research has been published in Current Biology.Sawfish Revealed as the
Ultimate Stealth Hunter
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 move-
ment 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 centimetres
above the ground creates almost no disturbance at all, which would
make stirring the river or sea bed difficult,” he said.
Co-author and Director of Sharks and Rays Australia, Dr Barbara
Wueringer, explained that “the shape of the rostrum is likely to
reduce noise in the water, increasing the ability of sawfishes to
detect minute vibrations caused by prey during their lateral swipes.
The results of our work will help us with a better understanding
of their habits and ultimately help us improve our conservation
efforts,” she said.Co-author A/Prof David Morgan from the Centre for Fish and
Fisheries Research at Murdoch University has tagged hundreds of
sawfish in the Fitzroy River, and worked closely with indigenous
ranger groups in the area. “We have encountered instances of
hunters removing the rostra as a kind of trophy,” he said. “The
findings of our study show just how instrumental sawfish rostra
are for their survival, and we would urge the few remaining human
population centres that have sawfishes inhabiting their local waters
to address this destructive phenomenon.”Courtesy A/Prof Bryan FryCredit: University of Newcastle