Tanya Plibersek has written to the Tasmanian government to flag she may reconsider the future of decade-old salmon farms in Macquarie Harbour due to concern about their impact on a critically endangered species.
It follows scientific warnings the salmon industry is having a “catastrophic” impact on the Maugean skate, an ancient fish thought to be found only in the vast harbour on the state’s west coast.
The federal threatened species scientific committee reported in September that “substantial recent evidence indicates a high risk of extinction for the species in the near future”, and recommended urgent action including reducing the amount of salmon to improve dissolved oxygen levels before summer.
In the letter to the Tasmanian premier, Jeremy Rockliff, on Monday, the environment minister said evidence considered by a skate recovery team had found better regulation and monitoring of “lower salmon farming industry loads” would be an important step in protecting the species.
“This last remaining population is under enormous pressure due to the low oxygen levels and poor water quality in the harbour,” the environment minister said in the letter, seen by Guardian Australia. “Urgent action must be taken to change this. Failure to do so will have implications for the long-term viability of important regional industries and jobs, especially in tourism and aquaculture.”
Plibersek said environment officials were examining three requests – from the Australia Institute, the Bob Brown Foundation and the Environmental Defenders’ Office – for a “reconsideration” of whether the salmon industry had the approvals it needed to operate in Macquarie Harbour. If the requests were found to have legal validity it would trigger “a broad consultation” with the state government, the salmon industry, its workers, their union and the community.
“If the reconsideration finds that the salmon industry in Macquarie Harbour does not have the necessary environmental approvals, [national environment law] would require operations to pause while approvals are sought,” Plibersek said.
“But I will look at any action I can take, consistent with my legal obligations… to support the Tasmanian government regulator, and the salmon farming industry, to put their operations on a truly sustainable footing.”
A decision to reconsider the approval of farms owned by Tassal, Petuna and Huon Aquaculture would likely spark a fierce response from the industry, and be opposed by it supporters in the Liberal state government and Labor opposition.
Writing in the Mercury last month, Luke Martin, the chief executive of the lobby group Salmon Tasmania, said: “Let’s be clear, this industry will not concede one single fish or one single job, and we caution environment minister Tanya Plibersek from being captive to loud green groups as she considers the future of the skate.”
Martin said salmon farming was one of several industries that operated in the harbour, and the scale of the industry had been reduced in 2017 without dissolved oxygen levels improving.
Studies have found the skate’s numbers have fallen due to the impact of salmon farms, hydro power stations altering upstream river flows, gillnet fishing and rising harbour temperatures due to the climate crisis.
The number of surviving Maugean skate is not clear, but an interim monitoring report estimated the population had slumped by 47% between 2014 and 2021. Scientists from the University of Tasmania said the species could be one extreme weather event from extinction.
Eloise Carr, Tasmanian director of the Australia Institute, said Plibersek’s letter showed the federal government was “taking the impacts of salmon farming on water quality seriously”. She said the industry and state government were trying to pressure the minister “to ignore the evidence”.
The federal and state governments each recently announced $2.1m funding to set up a captive breeding program to create a skate “insurance population”. The state government did not respond to a request for comment.
