Sawfish research along the Mitchell River
Since 2015, Sharks And Rays Australia (SARA) has been running regular expeditions to the Mitchell River in Cape York under the lead of Dr Barbara Wueringer, an expert on sawfish and other sharks and rays.
In July 2020, when COVID-19 travel restrictions to the Cape eased, SARA, together with Cape York NRM and Northern Gulf RMG, ran a research expedition to sample for sawfish along the Mitchell River.
‘Globally, sawfish are amongst the most endangered of all sharks and rays, and while four species are still found in Queensland’s waters, their numbers appear to be dropping, Dr Wueringer explains.
‘These large predators inhabit shallow coastal, inshore and riverine waters, making them susceptible to habitat modifications, gill netting and interactions with recreational fishers’.
Sites along the Mitchell River, located on Koolata Station, Highbury Station and on the exclusive native title lands of Kowanyama, were sampled using gill nets, drum lines and hand lines. Water samples were also filtered to allow collaborators from the Global Sawfish Search Project to check for sawfish eDNA—tiny particles of DNA shed by fishes into their environment.
In Kowanyama, the team was joined by the Kowanyama Land and Sea Rangers and Traditional Owners.
Dr Helen Penrose from Cape York NRM, who joined the expedition, acknowledges that ‘working with Indigenous Land and Sea Rangers to protect endangered species like sawfish is critical, as these animals are now restricted to extremely remote areas. The Traditional Owners are a respected and valued source of ‘Traditional and Contemporary Ecological Knowledge’ for threatened species conservation and management’.
‘The Mitchell River appears to be one of the strongholds for sawfish in Queensland, and so it is important that these animals are taken into account for environmental impact assessments of potential habitat modifications and water extractions’, explains Dr Wueringer.
Capture in gill nets is the main threatening process for sawfish so SARA continues to work with commercial inshore gill net fishers.
If you have seen a sawfish in Queensland, you can report your sighting to SARA via their online form www.cytags.com
The fieldwork has received funding from the Shark Conservation Fund, the Save Our Seas Foundation and the Sea World Research and Rescue Foundation Inc.