Leading scientists demand salmon ban in Tasmania’s Macquarie Harbour

Some of Australia’s most lauded scientists have intervened in the fight over salmon farming in Tasmania’s Macquarie Harbour, as Tanya Plibersek promises to ‘balance’ jobs and the environment.

Bob Brown Foundation activists erect a banner on a salmon pen in Macquarie Harbour.

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Some of the nation’s most eminent scientists have told Tanya Plibersek salmon farming in Tasmania’s Macquarie Harbour will cause an extinction and failure to halt it would be “unethical, indefensible”.

The federal Environment Minister must decide whether to repeal, amend or back-in 2012 environmental approval for fish pens in the remote harbour in Tasmania’s West.

Her rethink follows expert scientific advice that lower oxygen levels linked to salmon farms were having a “catastrophic” impact on the Maugean skate, a “living dinosaur” found nowhere else on earth.

The letter urging the pens to be removed is signed by more than 30 experts, including leaders in marine science, five fellows of the Australian Academy of Science, and immediate past chair of the Threatened Species Scientific Committee Helene Marsh.

“We call on you to revoke the 2012 decision that allowed expanded fish-farming and, instead, recognise the science that concludes that unacceptable impacts are occurring in Macquarie Harbour,” the letter says.

“This revocation and steps to reposition the Macquarie Harbour community are urgently required if the current path to extinction is to be avoided.

“The Maugean Skate is a prime example of the need to defend Australia’s unique ecosystems and species, which we have been fortunate to inherit from past generations, so that we can pass them on to future generations. Failing to do so when there are clear paths for action would be unethical and indefensible.”

Tassal salmon pens in Macquarie Harbour, Tasmania. Leading experts say the practice is catastrophic to the local environment. Picture: Mathew Farrell

The salmon industry has commissioned its own science, which concludes salmon farming’s impact on oxygen levels in the skate’s habitat are “negligible”.

“These findings highlight that the cessation of aquaculture in Macquarie Harbour alone without addressing other anthropogenic factors … would be most unlikely to resolve current low levels of dissolved oxygen,” Salmon Tasmania told the minister earlier this month.

Industry has also pointed to the skate monitoring data, which suggests that after an almost halving of the species’ population from 2014 to 2021, it has now stabilised at this lower level.

The experts’ letter to Ms Plibersek is signed by 14 professors, including marine or aquaculture scientists Stewart Frusher, Maria Byrne, Stephen Battaglene, John M. Pandolfi and Barbara Nowak.

Other prominent signatories include Andrew Wright, former executive secretary of the Commission for the Conservation of Antarctic Marine Living Resources, conservation biologist Professor Hugh Possingham, and former CSIRO Oceans and Atmosphere director Tony Worby,

“The extinction of the skate would be contrary to globally accepted norms for sustainable development and be inconsistent with Australia’s … international commitments,” the letter says.

Anti-salmon farm protesters against Tasmiania’s controversial fish farms. Picture: Amy Brown

Ms Plibersek said she would “follow the law and listen to the science”. “We’re committed to getting the balance right between environmental protection and sustainable economic development with job security,” she said.

On Wednesday, it was revealed more than a million kilograms of salmon died in pens in the harbour from September 2023 to March 2024.

Neighbours of Fish Farming said the deaths pointed to “overstocking” and “devastate the salmon industry’s claims of high standards of animal welfare”.

Salmon Tasmania CEO Luke Martin dismissed the claims. “Like all livestock farming, mortalities happen in our industry for many different reasons,” Mr Martin said. “There is no relevance between these numbers and the health of Macquarie Harbour.”