- Threatened Species Scientific Committee’s advice was clear: remove salmon biomass before summer
- Tasmania’s famed reputation for clean and green produce will be forever tarnished if the skate becomes extinct.
Salmon must be removed from Macquarie Harbour for the endangered Maugean skate to have any chance of survival, the Australian Marine Conservation Society (AMCS) and Humane Society International Australia (HSI Australia) said in their submission to federal environment minister’s Tanya Plibersek’s review of the issue.
The review is a critical step towards addressing the impact of salmon farming on the endangered Maugean skate, especially after the Tasmanian Environment Protection Authority in November renewed the Macquarie Harbour salmon farming licences for two years. Any delays in removing salmon from the harbour contradicts the independent advice from the Threatened Species Scientific Committee to the federal environment department, which said the key threat to the skate was poor water quality in Macquarie Harbour, primarily caused by fish farming.
The advice recommended to “eliminate or significantly reduce the impacts of salmonid aquaculture on dissolved oxygen concentrations” before this summer, which is rapidly coming to an end.
AMCS Shark Conservation Lead Dr Leonardo Guida said: “Federal environment minister Tanya Plibersek must take action and end salmon farming in Macquarie Harbour, and address the root cause to both save the skate and provide resilience to a World Heritage Area. What use are our nature laws, the Environment Protection and Biodiversity Conservation Act, if they don’t have the teeth to do exactly what the title of the act says? The situation has changed dramatically for the Maugean skate since the decision was made to allow salmon farming in Macquarie Harbour in 2012.
“Intensive salmon farming has caused oxygen levels to plummet in the Maugean skate’s only home, Macquarie Harbour, pushing the skate to the verge of extinction with fears fewer than 1000 remain. Since December two adults have died in the captive breeding program, highlighting the urgency to restore the health and resilience of the harbour.
“The federal environment department’s independent scientific advice clearly identified the reduction of salmon biomass to take place ahead of this summer.
“Tasmania’s famed reputation for clean and green produce will be forever tarnished if the skate becomes extinct. This could be the first time aquaculture has been the primary cause and directly driven the extinction of a marine fish.”
The AMCS-HSI Australia submission states: “This submission has outlined how the Particular Manner Notice attached to the Original Decision relied on Macquarie Harbour finfish farms’ adherence to (now outdated) Tasmanian regulatory processes which have failed to prevent significant adverse impacts arising from the Action on the Maugean Skate and the TWWHA [Tasmanian Wilderness World Heritage Area].”
The submission continues: “The submission has provided scientific evidence that so-called ‘adaptive management’ responses taken by Tasmanian regulators and finfish farms to date have been ineffective in improving the benthic and deep-water environment in Macquarie Harbour or in ensuring the ongoing survival of the remaining Maugean Skate population. Consequently, there is a clear and present danger that the Maugean Skate will become extinct in the wild within 10 years.”
HSI Australia Head of Campaigns, Nicola Beynon, said: “This is an extinction emergency. The Maugean skate must be listed as ‘Critically Endangered’ and given every chance to survive.
“Tasmania is home to Australia’s most infamous extinction, that of the thylacine or Tasmanian tiger. Does the state really want another extinction caused by human activity?”
 DCCEEW. “Conservation Advice for Zearaja Maugeana (Maugean Skate).” Australia: Department of Climate Change, Energy, the Environment & Water, 2023. http://www.environment.gov.au/biodiversity/threatened/species/pubs/83504-conservation-advice-06092023.pdf.
 Grant MI, Moreno D, Semmens J & Simpfendorfer C (2023) Population viability analysis of the Maugean skate Zearaja maugeana. Report prepared for the Australian Government Department of Climate Change, Energy, the Environment and Water https://www.dcceew.gov.au/sites/default/files/documents/75748.pdf