Sawfish

Threatened Status:

  • Freshwater (Largetooth) sawfish – Critically endangered (IUCN); Vulnerable (EPBC Act 1999)
  • Green sawfish – Critically endangered (IUCN); Vulnerable (EPBC Act 1999)
  • Dwarf sawfish – Endangered (IUCN); Vulnerable (EPBC Act 1999)
  • Narrow(tooth) sawfish- Endangered (IUCN); not listed (EPBC Act 1999)

Location:

  • Freshwater (Largetooth) sawfish – QLD, NT, WA
  • Green sawfish – QLD, NT, NSW (presumed extinct)
  • Dwarf sawfish – QLD, NT, WA
  • Narrow(tooth) sawfish – QLD, NT, WA

 

Sawfish are arguably the most iconic looking rays thanks to their saw-like snout (rostrum) that can extend up to 2m. Sawfish are among the world’s most endangered fishes¹. To save our sawfish, we must implement stronger levels of protection for them and reduce fishing pressure.

About Sawfish

  • Sawfish are in fact rays. Unlike sharks, rays have their gills underneath whereas sharks have gills on the side.
  • Newborn sawfish are born with their saws covered in a sheath of tissue to protect the mother.
  • Freshwater sawfish are the only sawfish to live in freshwater as the name suggests. They’ve been found as far inland as 800km south of the coastal city of Darwin and are depicted nearby in rock art by indigenous Australians². All other sawfish typically travel as far upstream as the tidal reaches where the water is still a little salty.
  • Their ‘saws’ (rostrum) are used for defense, detecting and chopping up prey such as other fish.
  • Sawfish have some of the most expensive fins in the fin trade, fetching ~US$4000 for a set, and their saws can sell for US$100’s as trophies or curios³.
  • Sawfish have lost over half their habitat worldwide. Australia is a ‘life-boat’ for the four of the world’s five species. Northern Australia represents one of the last viable populations thanks mostly to its remoteness and relatively untouched coastline.
  • Although exact sawfish populations are unknown in Australia, they are acknowledged to have experienced dramatic declines due to historical fishing. They are presumed extinct in NSW (last seen in 1972)⁴, and have largely disappeared from the entire east coast of Australia (with exception to the narrow sawfish).

Why are sawfish endangered in Australia?

Historical fishing pressures are largely to blame for the dramatic decline in sawfish numbers. Because of their saw-like snout – or ‘rostrum’ – they’re easily caught in gillnets and trawler nets that scour the seafloor where they live. Fishing pressures have been so great that the green sawfish (Pristis zijsron) was last seen in NSW in 1972 and is presumed extinct in NSW waters. Many sawfish have nearly all but disappeared from the entire east coast of Australia (with exception to the narrow sawfish).⁵

Although it is now illegal to target sawfish when fishing, many fishers in the past targeted them for their sheer size (up to 7m long!) and to keep their saw as a trophy. It’s not uncommon to come across pubs and homes across northern Australia that have trophy saws on their walls – so much so that researchers have asked people to report sightings or photos of saws to get an idea of their historical distribution!⁶

In 2000, sawfish were first listed for protection under Australia’s national environmental law, the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Although it is illegal to target or trade sawfish, there are still weaknesses in their protection under the EPBC Act. Sawfish are currently listed as “Vulnerable” but this is outdated as a scientific assessment in 2018 re-classified all of Australia’s sawfish as either “Endangered” or “Critically Endangered” under the same criteria the EPBC Act uses. Narrow sawfish are still yet to be listed under the EPBC Act, however the good news is that it’s nomination for listing is currently on the Federal Environment Minister’s desk awaiting a decision.

 

What are the threats to sawfish?

Commercial fishing

Sawfish are vulnerable to gillnets and trawlers because of their saw-like rostrum that gets easily tangled in nets. Along northern Australia, they’re often accidentally caught in gillnets used to catch barramundi, or trawler nets used to scoop up prawns. 

Being rays, sawfish are typically resilient to capture because they don’t have to move to breathe. However, there are allegations some fishers chop their saws off, resulting in a gruesome and prolonged death.

Why chop a saw off? Some fishers do so because of a combination of a perceived inconvenience to their fishing, concerns that their nets could be costly to fix because of the damage caused trying to release the sawfish, and a fear for their own safety. The loss of saw means the sawfish often dies of blood loss and starvation anytime from days to weeks later.⁷

In trawlers, they can be squashed as the catch gets hauled out of water, maimed by other animals in the trawl net, and even have their snagged saws snapped off as they’re forced through to the back of the trawl net.

Increasing population and coastal development.

As the human population increases, so too comes the demand for better infrastructure, including bigger ports, and the creation of dams to for irrigation. The creation of dams that change river flows can block the upstream migration of juvenile sawfish, or create isolated pools exposing sawfish to starvation or worse… the drying out of those pools! Compounding this is the effect of the climate crisis, and the changing frequency of flood events which sawfish rely on for reproduction.⁸

Solutions!

The challenges seem daunting, but we have solutions at the ready. We can protect river mouths from gillnetting, which are known habitats that are critical to the survival of these animals. Finally, we can support and advocate for the transition to renewable energy to limit the impact of the climate crisis – not just for sawfish, but for all life on Earth.

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References:
  1. International Union for the Conservation of Nature (IUCN) Shark Specialist Group. “Saving Sawfish. A Strategy to Recover World’s Most Endangered Marine Fish” https://www.iucnssg.org/uploads/5/4/1/2/54120303/sawfish_infographicv2_copy.pdf
  2. https://www.abc.net.au/news/2018-04-16/sawfish-find-surprise-indigenous-rock-art/9662032
  3. International Union for the Conservation of Nature (IUCN) Shark Specialist Group. “Saving Sawfish. A Strategy to Recover World’s Most Endangered Marine Fish” https://www.iucnssg.org/uploads/5/4/1/2/54120303/sawfish_infographicv2_copy.pdf
  4.  NSW Department of Primary Industries. “Threatened Species. Green sawfish.” https://www.dpi.nsw.gov.au/fishing/threatened-species/what-current/extinct/green-sawfsh 
  5. Wueringer, BE (2017) Sawfish catches in the Queensland Shark Control Program, 1964 to 2016. Endangered Species Research, DOI:10.3354/esr00853 open access
  6.  Sharks and Rays Australia. “Report Your Sighting” https://www.sharksandraysaustralia.com/report-your-sighting/
  7. Morgan, D et al. (2016) What is the fate of an amputee sawfish? Essays, Fisheries Magazine. Feb 2. https://fisheries.org/2016/02/what-is-the-fate-of-amputee-sawfish/
  8. https://www.abc.net.au/news/2019-12-24/sawfish-boom-and-bust-cycle-at-risk-with-dams/11798542