The Daintree

The Daintree

access the original blog post for the Save Our Seas Foundation here

WEURINGERbarbara - the Daintree

The Daintree River is surrounded by lush rainforest. Photo © Barbara Wueringer | Sharks And Rays Australia

WEURINGERbarbara - the Daintree

Native species of taro and freshwater mangroves fringe the shoreline. Photo © Barbara Wueringer | Sharks And Rays Australia

Our search for sawfishes in the waters of the northern parts of Queensland, Australia, certainly takes us into some very special ecosystems. Most are classified as arid bush or grassland, but recently our search took us to the Daintree, a special place that deserves its own blog post.

WEURINGERbarbara - the Daintree

A bridge crosses a side arm of the Daintree. The main river can only be crossed by car ferry. Photo © Barbara Wueringer | Sharks And Rays Australia

Australia is the driest continent on earth – nearly 20% of its landscape is defined as desert – and is well known for this fact. The unique landscape of the outback and its drought-adapted fauna, such as termites, kangaroos and emus, are famous and for many people they represent the true Australia. But a large number of these species actually evolved from an ecosystem that is now restricted to the Wet Tropics in Far North Queensland – the Daintree.

WEURINGERbarbara - the Daintree

The trunk of this tree is completely overgrown by a fern. Photo © Barbara Wueringer | Sharks And Rays Australia

WEURINGERbarbara - the Daintree

One of six amethystine pythons that were resting in a tree above our sampling site. Photo © Barbara Wueringer | Sharks And Rays Australia

The Daintree is the oldest rainforest in the world. As the climate remained stable over millions of years in this region, many of the native plants have retained their ancestors’ ‘primitive’ characteristics. Of the 28 lineages of near-basal, or ‘primitive’, flowering plants that exist globally, 16 are found in the Daintree. The Daintree is often advertised as the place where the rainforest meets the Great Barrier Reef, so just imagine the species diversity that can be encountered within a few hundred kilometres! Saltwater crocodiles, cassowaries, tree kangaroos – these are only a few of the local flagship species.

WEURINGERbarbara - the Daintree

A freshwater mangrove flowering in the Daintree, Far North Queensland. Photo © Barbara Wueringer | Sharks And Rays Australia

The name Daintree refers not only to the rainforest, but also to the river that flows through it. And this is where we went searching for sawfishes. We spent five days and nights sampling in the river, far inland where the water becomes more and more fresh. On this particular trip we did not catch any sawfishes, but we did tag and release some juvenile bull sharks. Currently, the distribution of sawfishes on the east coast of Far North Queensland and the Cape York region is considered to be patchy, but this may be because so little attention has been paid to it and sampling efforts have been incomplete.

WEURINGERbarbara - the Daintree

A juvenile bull shark is carefully untangled from a gill net. Photo © Barbara Wueringer | Sharks And Rays Australia

WEURINGERbarbara - the Daintree

The team from Sharks And Rays Australia works up a juvenile bull shark. © Barbara Wueringer | Sharks And Rays Australia

Locals in the tiny village of Daintree were super interested in our work and by the time we launched our boat there were 20–30 people watching us (about 20% of the population!). We also distributed our sawfish ID flyers (adapted from the Sawfish Conservation Society for Queensland; download here). Next time we come back we’ll be sure to give a public talk.

WEURINGERbarbara - the Daintree

Barbara distributes our flyers in Daintree village, encouraging people to submit sawfish sightings. Photo © Amandine Bart | Sharks And Rays Australia


The saw-less sawfish?

The saw-less sawfish?

Access the original blog post written by Barbara for the Save Our Seas Foundation here.

The first time I saw a sawfish, I was mesmerised. The question that sprang instantly to mind – and also the one that I get asked the most – is, what is the saw used for? To say that I found this question fascinating is an understatement, as I spent four years of my life trying to answer it. My PhD project, which I finished in 2011, focused on the feeding behaviour and sensory biology of sawfishes. And I can tell you already, the deeper I got into the topic, the more fascinating it became.

The saw is an elongation of the rostral cartilage. The elongated rostrum, which also bears lateral teeth, evolved at least three times independently in elasmobranchs: twice in rays and once in sharks – in the family Sclerorhynchidae (extinct sawfish), the family Pristiophoridae (sawsharks) and the family Pristidae (living sawfish). For my research I compared sawfishes with their close relatives the shovelnose rays of the family Rhinobatidae. As both taxa are likely to have evolved from a common ancestor that was similar to shovelnose rays, the comparison enabled me to provide a hypothesis about the evolutionary benefit of the saw in living sawfishes.

My research found that the freshwater sawfish Pristis pristis uses its saw both to sense prey (via electroreception and touching) and to manipulate it. Interestingly, juvenile freshwater sawfishes slash at an electric dipole, which resembles visually hidden prey, only when it is suspended in the water. Shovelnose rays hardly react to these fields. When a sawfish encounters an electric dipole field on the bottom, just like a shovelnose ray it tries to gobble up the field source with its mouth. These results clearly indicate that the evolution of the saw enabled sawfishes to expand their hunting strategy to include fast, free-swimming prey.

The saw, however, is also what gets sawfishes into trouble. Saws easily get entangled in fishing gear and the sawfishes wrap themselves up even more in nets when they try to escape from the invisible danger, sometimes becoming dangerous to handle. Saws are also sought-after trophies. Even though all species of sawfish are listed on CITES and the four species in Australia are protected locally under federal and state legislation, saws can still sometimes be found for sale at local markets or on e-bay.



I had always thought that fishermen were taking whole sawfishes and selling the fins separately from the saws. After all, sawfish fins are among the most valuable in the international shark-fin trade and can fetch a few thousand dollars each. But there is a different, even more disturbing practice. Fishermen, both commercial and recreational, are cutting off a captured sawfish’s saw before releasing the animal alive. Although I had heard rumours about this practice, it was only in November 2015, when we finally ran the first research expedition with Sharks And Rays Australia to the Norman River, that I started to realise just how much of an issue it could be.

Situated in the south-eastern corner of the Gulf of Carpentaria, the Norman River is a Mecca for commercial and recreational fishermen who are after barramundi. It is fairly accessible, being one of the few destinations in the Cape York region that can be reached by a paved road. Moreover, public concrete ramps enable boats to be launched easily at Normanton, which lies inland on the river, and at the coastal fishing port of Karumba.


bw-img_2339-sm During the closed season for barramundi fishing, the boats parked in the Karumba gardens overshadow the houses. Photo © Barbara Wueringer | Sharks And Rays Australia.


Setting, checking and retrieving gill nets in this river was an adventure. We were manoeuvring in waters with an average visibility of 10 centimetres (four inches). Hidden under the surface were landscapes of boulders, sunken logs and sand bars that were only visible with the aid of modern technology. The presence of large saltwater crocodiles took the required alertness and protocols to the next level. We had prepared for encounters with all kinds of creatures, from our study species to sand flies, mosquitoes, stingrays and stingers. What made the sampling even more difficult was that the river was full of jellyfish. Our net setting required fine-tuning.

After four days of sampling we managed to capture, tag and release one juvenile bull shark and one sawfish. I don’t think that this low sample number reflects the sawfish population of the Norman River, but it will take many more field trips to find out. As a result of our outreach efforts while we were at the Normanton Tourist Park, we received reports of two accidental sawfish captures that took place just days before we arrived. When the sawfishes were captured by recreational fishermen, the saws of both were already missing. The fishes were released alive, but their chances of survival are slim.


Can you see the crocodile's foot prints? The entrance to a hide out of a saltwater crocodile Crocodylus porosus. The belly slide is around 50 cm wide, indicating a large animal. The entrance to a nesting site of a saltwater crocodile Crocodylus porosus. The belly slide is around 50 cm wide, indicating a large animal. Photo © David Nash | Sharks And Rays Australia


A group of pelicans - which is called a pod - in the southern Gulf of Carpenteria A group of pelicans is called a pod! Photo © David Nash | Sharks And Rays Australia.


Together with the Save Our Seas Foundation Media Unit, the material submitted was turned into an educational video so that this sad occurrence could be turned into an opportunity for public education. Please share it widely.




  • In countries where sawfishes are protected, the removal of a sawfish’s saw is illegal.
  • As sawfishes are listed by CITES (the Convention on International Trade in Endangered Species), any international trade in sawfish body parts or live animals is regulated.
  • In Australia sawfish are protected under the EPBC Act.
  • When the saw of a live sawfish is removed, the brain cavity is opened, resulting in the sawfish’s slow, lingering death.
  • A sawfish uses its saw to find and manipulate its prey. It also uses it to defend itself.


Further reading
Morgan DL, Wueringer BE, Allen MG, Ebner BC, Whitty JM et al. 2016. What is the fate of amputee sawfish? Fisheries 41(2): 71–73.
Seitz JC, Poulakis GR. 2006. Anthropogenic effects on the smalltooth sawfish (Pristis pectinata) in the United States. Marine Pollution Bulletin 52: 1533–1540.
Wueringer BE, Squire LJ, Kajiura SM, Tibbetts IR, Hart NS et al. 2012. Electric field detection in sawfishes and shovelnose rays. PLOS ONE 7: e41605.
Wueringer BE, Squire LJ, Kajiura SM, Hart NS, Collin SP. 2012. The function of the sawfish’s saw. Current Biology 22: R150–R151.


The sawfish's gills are flushed with water during the work up. Teagan Marzullo and Barbara Wueringer tag the first juvenile freshwater sawfish, Pristis pristis, captured for this study. Photo © David Nash | Sharks And Rays Australia.


dn-img_2411-xs SARA’s field team posing in front of a croc statue in Normanton, Queensland © David Nash | Sharks And Rays Australia.


The fate of amputee sawfish

The fate of amputee sawfish

Read more about our recent paper in the press release by Murdoch University, which is copied below.

Murdoch researchers highlight the cruelty of amputating sawfish rostra

February 18, 2016

A Green Sawfish with its rostrum amputated (Pic: David Morgan)

The cruel act of amputating distinctive sawfish rostra for trophies should be afforded the same attention as the poaching of body parts from other endangered species like rhinos, a Murdoch University researcher has said.

Associate Professor David Morgan from the Freshwater Fish Group & Fish Health Unit said sawfish protection needed better enforcement globally and the conservation value of sawfish should be actively promoted.

Available evidence suggests sawfish die a lingering death after rostrum removal, he said in an article published in the Fisheries journal.

Their rostra – the chainsaw-shaped extension that distinguishes the fish and gives it its name – are used to sense, forage for and capture their prey of crustaceans and small fish.

“Sawfish forage on the riverbed and sense prey via the electrosensitive pores on their rostra,” explained Dr Barbara Wueringer, who co-authored the study.

“They then slash their rostrums to stun or impale their food. They also use the rostrums to protect themselves from predators.”

Professor Morgan and his team studied the behaviour of a Green Sawfish found in the Ashburton River after its rostrum had been illegally amputated. They tagged it and observed changes in movement patterns and habitat use compared to similarly sized sawfish with rostra intact.

“We found that it ranged more widely, perhaps in order to source ‘easy prey’ or avoid attacks by predators, than other tagged sawfish of a similar size with rostra intact,” he said.

“After 75 days the fish was no longer detected and may have either emigrated outside the detection range or, more likely, it will have perished because emigration occurred infrequently for other tagged sawfish of that size.”

At a later date, Professor Morgan also captured and tagged a Freshwater Sawfish with a partially severed rostrum contained in an isolated freshwater pool in the Fitzroy River.

He said it was severely emaciated and its damaged rostrum had impacted its ability to effectively forage.

“It was detected by our loggers for 10 days and not thereafter. In comparison, two other similarly sized individuals tagged in the same pool at the same time were detected for several months. This supports our assumption that the injured sawfish died in the pool.”

Professor Morgan said the decline of sawfish due to fishing pressure was exacerbated by humans removing sawfish rostra.

“This undoubtedly negatively impacts survival rates of those fish,” he added.

“Most amputations in northern Australia are from the last few decades.

“The few remaining human population centres that have sawfishes inhabiting their local waters must address this destructive phenomenon, and sawfish protection needs better enforcement globally.”

The Fisheries paper can be read here.