Tasmania’s environment department argued for the Maugean skate not to be listed as critically endangered, saying existing conservation advice relies heavily on “uncertain, outdated or otherwise contested” information.
The department has also argued that salmon farming should no longer be listed as having a “catastrophic” impact on the skate, because of recent water quality data showing an improvement in dissolved oxygen levels in Macquarie Harbour.
What’s next?
A decision on whether the endangered Maugean skate’s status was upgraded to critically endangered was set for late October but has been delayed by up to 12 months.
Tasmania’s environment department pushed for the Maugean skate’s threatened species status not to be upgraded to critically endangered, arguing draft conservation advice “relies heavily on information, data or assumptions that are highly uncertain, outdated or otherwise contested”.
In a submission to the federal department, Tasmania’s Natural Resources and Environment Department (NRE) secretary Jason Jacobi said many changes had occurred since draft conservation advice was published in September 2023.
That advice highlighted the “fastest and simplest” way to improve oxygen levels in Macquarie Harbour was for a significant destocking of salmon farms by last summer, a recommendation that did not occur.
In his submission, Mr Jacobi argued recent surveys of skate population numbers, which found the population appeared to have stabilised at “very low levels”, did not support “several key assumptions on which the draft conservation advice and listing assessment heavily relies”.
“This includes a strong indication that the estimated mature population size of 40 to 120 [individuals] in 2023 is a miscalculation and underestimates the true current population size,” he said in his submission.
An Institute of Marine and Antarctic Studies report in 2023 said the skate’s population had declined by 47 per cent between 2014 and 2021, and warned one significant weather event would be enough to push the species to the brink of extinction.
Mr Jacobi also argued projections of future skate population decline, which was reviewed by University of Tasmania conservation ecologist Barry Brook in salmon industry-funded research was “now out of date and cannot be relied upon to provide meaningful population estimates”.
Professor Brook wrote to federal Environment Minister Tanya Plibersek following his review, saying the projections “cannot be relied upon to draw firm conclusions about the future of the Maugean skate” and called for the projections to be “redone from the ground up”.
The state government has since convened an “expert technical panel” to review and update the projections.
Government push to not upgrade skate’s threatened species status
In a briefing note to Ms Plibersek recommending an extension to the up-listing decision, released under right to information laws, her department said the projections “always intended an iterative analysis updated and revised when new information becomes available”, and future decisions would be informed by updated projections.
“The department is confident the recovery team has already agreed an appropriately rigorous process to ensure the [decision] is scientifically sound and updated when new information becomes available,” the briefing note to Ms Plibersek said.
Mr Jacobi also told the department that water quality data indicating improved dissolved oxygen levels in the harbour showed “water quality can improve significantly, concurrent with salmon farming”.
“As such, the consequence of salmon farming causing water quality impacts to the skate can no longer be considered to be ‘catastrophic’ and the Tasmanian government considers that when the existing management framework is recognised, the residual risk rating should be amended to a lower-consequence category,” he said.
“I therefore do not support the updating of the conservation advice or the up listing of the species at this time.”
The Tasmanian government agrees with its environment department that the Maugean skate’s threatened species status should not be upgraded, and that “the science tells us the skate and the salmon industry can co-exist”, a spokesperson said.
“Oxygen levels in Macquarie Harbour are at the highest levels seen in more than decade, which shows the actions taken to date are working,” the spokesperson said.
“It is time for the federal Labor government to stop playing games with the livelihoods of hardworking Tasmanians and end the years of delays and indecision.”
In a separate process, Ms Plibersek is considering whether to review a 2012 decision to approve an expansion of salmon farming operations in the harbour, following Environment Protection and Biodiversity Conservation Act referrals from three environmental groups concerned by the decline of the skate.
There’s no deadline for when that decision needs to be made, with stakeholders on all sides of the debate calling for a decision to be made as soon as possible.
Advice to protect skate from decade of science, Greens say
Tasmanian Greens leader Rosalie Woodruff said she was concerned by the department’s submission, and that there was “strong evidence from years of research” that the Maugean skate was in decline and under threat.
“The conservation status of threatened species should be informed by the most robust scientific evidence,” Dr Woodruff said.
“Unfortunately, we are seeing the Tasmanian government choosing to ignore a decade of scientific findings and instead claim a small number of recent preliminary test results in a narrow region mean the Maugean skate is not at increased risk.
“It’s good news there’s been some positive test results recorded in Macquarie Harbour, but it is reckless to assume this means there’s no longer anything to worry about. We need to do everything we can to try to save this ancient species from extinction.
“The idea the Maugean skate should be listed as critically endangered has come from more than a decade of science, and it’s not something that’s been suggested lightly.”
Salmon Tasmania chief executive Luke Martin said the industry “doesn’t deny concerns around the skate”, but said upgrading its threatened species status to critically endangered would “have implications for the management of the harbour that will affect all its users”.
“Right now, the population estimates are still highly contested and also where the population concentrates within a huge harbour,” he said.
“It’s not at all surprising the Australian government’s threatened species committee asked for a further 12 months to allow more research to be undertaken.
“Our point is, in the meantime, we don’t think it’s fair or just for our workers and the West Coast community to be left in limbo by this now politically charged process with no clear end in sight.”