The Tasmanian endemic Maugean skate (Zearaja maugeana) is listed as endangered under both Tasmania’s
Threatened Species Protection Act 1995 and the
Environment Protection and Biodiversity Conservation Act 1999.
The Department of Natural Resources and Environment Tasmania (NRE Tas) has developed a Conservation Action Plan (CAP) for the species. The CAP identifies priority research and conservation management actions for recovery of the species.
The species is also a priority under the Australian Government’s Threatened Species Strategy Action Plan 2022-2032.
The Maugean skate is a medium-sized species, with mature females reaching a maximum of 84cm in total length, and males reaching a maximum of 70cm.
Male Maugean skate can be told apart from females by the presence of claspers at the beginning of the tail.
The Common thornback skate (Dentiraja lemprieri) also occurs in Tasmanian estuaries, and can be differentiated from the Maugean skate by its:
long and narrow claspers
Maugean skate. Copyright Jane Rucker/IMAS
Why is the Maugean skate threatened?
Two of the key threats to the Maugean skate are habitat degradation and loss, particularly documented declines in dissolved oxygen levels and in sediment health, and unintended mortalities from entanglement in fishing nets set to catch other species.
Other identified potential threats or limiting factors include:
predation (for example from fur seals and parasitic sea lice)
pollution, such as from historic mining runoff
habitat changes linked to altered river flows from hydroelectric production
increased nutrient loadings from aquaculture operations
low genetic diversity and inbreeding
climate change impacts
Need for conservation action
skate is known only from Macquarie Harbour and Bathurst Harbour, on Tasmania’s remote west coast. However, the status of the population in Bathurst Harbour has long been uncertain, with only four individuals ever caught from this location.
Recent research by the Institute of Marine and Antarctic Studies (IMAS) shows that Macquarie Harbour is now considered to hold the sole remaining viable population of the species.
monitoring shows that the remaining skate population in Macquarie Harbour has also declined in recent years, including a likelihood that a significant proportion of the population may have died during 2018 and 2019. There are also signs of decreased breeding success for the remaining population.
Together, these factors suggest that the species faces a high risk of extinction, that every skate is now important to the survival of the species, and that urgent conservation actions are required to stabilise and recover the skate’s population.
What is being done to help the Maugean skate?
The CAP for the Maugean Skate identifies priority research and conservation management actions for recovery of the species, many of which are currently underway. It builds on a range of earlier conservation actions undertaken by theTasmanian Government to reduce the likelihood of extinction for the species.
Publication of a Listing Statement
Listing Statement provides a basis for detailed conservation planning. It summarises contemporary species and population data, identifies threats to the species and outlines research and conservation and management needs.
Changes to gillnetting rules in Macquarie Harbour
Recent research indicates that Maugean
skate sometimes rely on shallow areas of Macquarie Harbour to access highly oxygenated water. This behaviour increases the likelihood that skate may encounter gillnets set to catch other species. Gill-nets set for long periods of time increase the chances of mortality for any skate entangled. Interim measures for gillnetting in Macquarie Habour were introduced in November 2022 to minimise the risk of interactions between skate and fishers. The measures were formalised in November 2023.
Ensure viable habitat in Macquarie Harbour
In September 2022, the Environment Protection Authority (EPA) issued a
Total Permissible Dissolved Nitrogen Output for Macquarie Harbour, to improve environmental indicators including levels of dissolved oxygen. This determination reduced dissolved nitrogen outputs by approximately 10% compared with 2021 levels. The EPA has also developed dissolved oxygen targets for Macquarie Harbour. Additional actions to ensure a viable habitat for the Maugean skate in Macquarie Harbour are detailed in the CAP.
Community education and awareness
The people of the West Coast have shown a long-term interest in Maugean skate conservation and a willingness to share local knowledge and participate in citizen science actions. In 2023, NRE Tas held a series of meetings in Strahan and Queenstown to better understand the varying views, interests and impacts across the West Coast community.
Community engagement has also been undertaken through the Cradle Coast Natural Resource Management’s Maugean Skate Awareness Project, which used a variety of community-based activities to engage with diverse audiences on the topic of skate conservation.
National Recovery Team for the Maugean Skate
Information relating to the National Recovery Team for the Maugean Skate is now located on the Cradle Coast Natural Resource Management’s Maugean skate Recovery Team webpage.
DCCEEW have developed a Fact Sheet on Maugean Skate Conservation under the Environment Protect and Biodiversity Conservation Act 1999.