Global Sawfish Search
In order to protect the five species of endangered sawfishes, we need to know where they can still be found today.
We’re working with sawfish experts around the world to undertake a global sawfish survey using environmental DNA (eDNA).
Sawfishes are considered the most threatened group of marine fishes, with all five species on the IUCN Red List as Critically Endangered or Endangered. Sawfishes have disappeared from at least 20 countries in their historic range and are possibly extinct in many more due to fishing pressure and habitat loss.
Sawfishes are large enigmatic rays that occur in tropical and subtropical coastal ecosystems. There are five species of sawfish, each bearing the distinct toothed rostrum that makes the species iconic. Sawfish are culturally significant in many coastal and native communities throughout the world and biologically important to the inshore and coastal ecosystems that they inhabit.
The rarity of sawfishes makes studying sawfish using traditional surveys largely ineffective, unreliable and cost-prohibitive, at the scales needed to locate now scarce individuals. Additionally, the lack of data on their current occurrence and distribution makes their conservation significantly more difficult because it is hard to know where to focus limited conservation resources to ensure that sawfish are not lost from more countries and to start recovering them in areas where they remain.
More information can be found via the Sawfish Conservation Strategy
This project will enhance global conservation efforts for sawfishes by using environmental DNA (eDNA) techniques to undertake a global survey of their current distribution (Simpfendorfer et al. 2016).
Field and laboratory techniques will be validated for all five sawfish species, a global sampling plan developed and implemented, and the results synthesized to produce revised current distributions of sawfish species. The results of the study will be critical in improving conservation outcomes for sawfish by identify focus areas for research, monitoring and conservation
A large contingent of the field work will be carried out by sawfish researchers around the world.
An eDNA Field Kit that contains all the necessary equipment for sampling will be sent to collaborators, who will then collect samples in key locations throughout the world.
After sample collection, the eDNA Kit and samples will be shipped back to James Cook University, Townsville, Australia, where the eDNA will be analysed for the presence of sawfish DNA.
All organisms continuously leave a trace of their DNA behind in the environment. This DNA can be in the form of skin cells, bodily fluids, metabolic waste, gametes, or blood.
Environmental DNA (eDNA) analysis is based on the collection of this material, commonly by filtering water from the environmental source.
eDNA is a rapid and non-invasive method for collecting and analyzing samples from the environment without contact with the target species, which is the ideal solution for studying elusive sawfish.
Process of sampling eDNA involves filtering water with material captured on fine filter paper. The filter paper is then stored and sent back to the lab for analysis.
eDNA sampling in Everglades National Park, Florida, USA. Photo credit John Carlson
Catch and tag of juvenile smalltooth sawfish in Everglades National Park, Florida, USA. Photo credit
Sawfish outreach event with Phillips Lab at Discovery Day, Dauphin Island, Alabama. Photo credit Nic
eDNA sampling in Exmouth Gulf, Western Australia. Photo credit Vinay Udyawer
Juvenile smalltooth sawfish rostra from Everglades National Park, Florida, USA. Photo credit John Ca
Tampa Bay, Florida, USA with Havenworth Coastal Conservation. Photo credit Tonya Wiley
eDNA sampling in the mouth of South Alligator River, Kakadu, Northern Territory. Photo credit Pete K