Two adult Maugean skates were successfully released back into Macquarie Harbour in late April, by the Institute for Marine and Antarctic Studies (IMAS) and members of the Tasmanian Aboriginal community, who were working with IMAS researchers when the animals were first collected from the Harbour in December 2023.
IMAS marine ecologist and captive management program leader, Professor Jayson Semmens, said returning the skates to Country as they approach the end of their natural lifespan was an important step – for the Aboriginal community, the researchers, and the skates themselves.
"The data is showing oxygen in the Harbour has currently increased relative to historical low levels and, alongside the broader work undertaken to prepare the skates, it is an appropriate time to put them back," Professor Semmens said.
"We have fitted them with tracking devices to monitor their movements, but this release goes beyond survival. It is about honouring the incredible contribution they've made to our understanding of their species, and also to our captive population."
"It's also important for our Aboriginal community, who've worked with us from the beginning, providing knowledge and guidance that has helped us create holding facilities where our captive population can thrive and may ultimately help to rebuild the Maugean skate population in our waters."
IMAS Junior Research Fellow and program co-lead, Bailee Woolley, said it has been important to have both an adult female and male in captivity to understand more about the species – the different behaviours they exhibit, and their reproductive biology.
"Since their capture in 2023, these two adult Maugean skates have demonstrated that the species can thrive in captivity," she said.
"The female skate has laid more than 400 eggs, fertilised with sperm she stored from earlier matings in the wild, and these have produced 79 live hatchlings to date.
"We also now have the male's DNA, as we have collected sperm from him which we'll preserve for potential use in the future."
To prepare the skates for their return to the wild, IMAS researchers have been conducting acclimation trials since late last year, which are designed to reactivate the skates' natural instincts.
"As the Harbour is naturally low in oxygen, this has involved gradually reducing oxygen levels in their tanks so they're ready for a lower oxygen environment again – and getting them used to a wild diet which will be mainly crabs when they return to the Harbour," Professor Semmens said.
"This training process has given us such valuable experience, because we now know how to successfully prepare animals for release in the future."
IMAS Fisheries and Aquaculture Centre Head, Professor Sean Tracey, acknowledged the collaborative effort underpinning the recent release of two adult Maugean skate into Macquarie Harbour, recognising the contributions of the IMAS research team, the Tasmanian Aboriginal community, the local Strahan community, and both the Tasmanian and Federal Governments.
"This milestone reflects a coordinated and sustained effort across research, community and government partners. We acknowledge the valuable support from the Department of Natural Resources and Environment Tasmania (NRE Tas), which underpins research on the Maugean skate in Macquarie Harbour, and the significant financial contribution from both the Australian and Tasmanian Governments," Professor Tracey said.
"The combined support from the Tasmanian and Federal governments has enabled a deeper understanding of the species and strengthened the scientific basis for recovery.
"Alongside the contributions of local and Indigenous communities, this work is improving our capacity to support the long-term persistence of this endangered species."
The captive management program at the University of Tasmania's Institute for Marine and Antarctic Studies (IMAS) is supported by funding from the Australian Government's Saving Native Species, and Natural Heritage Trust Programs through the Cradle Coast Authority, and funding from the Tasmanian Government's Department of Natural Resources and Environment Tasmania (NRE Tas).
Cover image: Swimming free!
Credit: Mark Priest IMAS
