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Macquarie Harbour oxygen levels declined in 2025, shows new EPA data

 

The data also comes after a NRE report was quietly published that revealed the Tasmanian Government's intention to increase salmon farm licences from annual renewals to 10 years - meaning decade long approvals. 

 

“Given the shock revelation that the Tasmanian Government is planning to shift to 10-year licenses, at a time when climate change is exacerbating pollution impacts in our waterways, now more than ever we need the federal Environment Minister to step in and take the critical actions necessary as it is obvious the state is failing to prioritize the long term survival of skate.”  Said Jess Coughlan, Senior campaigner at Environment Tasmania 

 

Data released by the EPA late Friday afternoon shows dissolved oxygen levels in the Maugean skate’s only home, Macquarie Harbour, were declining during the second half of 2025. 

 

Oxygen levels were in the ‘red’ for the depths in the middle of the harbour as well as within the harbour located in the Tasmanian Wilderness World Heritage Area - despite the much publicised efforts of the oxygenation program.

 

The data comes weeks after the renewed Endangered listing of the skate and updated Conservation Advice that reconfirmed salmon farming to be “catastrophic” to the skate’s survival. The Advice urges the reduction of salmon farming over the next 12 months to bring oxygen levels back to pre-2009 levels in the harbour. 

 

“Environment Minister Murray Watt stated he would take the critical actions needed to save the skate. Well, this data confirms we need the Conservation Advice to be implemented in full and that means removing salmon from Macquarie Harbour” Said Jess Coughlan, campaigner at Environment Tasmania.

 

The EPA also notes that natural oceanic recharges occurred in January and February 2026. 

 

“The harbour and the skate were extremely lucky that Mother Nature has provided some reprieve. But we can’t rely on luck to save a species. Climate change is increasing the likelihood of more extreme weather events in Macquarie Harbour. Without addressing the root cause of the oxygen problem – salmon farming – it’s likely we can expect to see further skate populations crashes, such as the two that happened in the harbour in 2019 resulting in significant skate deaths” said Jess Coughlan

 

EPA data: https://epa.tas.gov.au/business-industry/regulation/salmon-aquaculture/macquarie-harbour-dissolved-oxygen

NRE report with plans to extend licensing period to 10 years on page 4 https://nre.tas.gov.au/Documents/Reflections%20and%20Learning%202025%20Salmon%20Mortality%20Event%20-%20Progress%20Report.pdf



All comments attributed to Jess Coughlan

Senior campaigner at Environment Tasmania

0431684741

[email protected]

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