Last updated February 22, 2019 at 5:07 pm
Experts say a Federal Government-released report into New South Wales fish deaths has failed to consider the effects of climate change.
They were the grim scenes that shocked Australia and made headlines across the world: three separate fish kills taking place in rapid succession in western NSW, resulting in the deaths of millions of fish.
The Federal Government last night released an independent interim assessment, which suggests continued hot conditions, combined with a lack of water flow, caused weir pools to form layers of water – an upper oxygenated layer and a lower layer lacking in oxygen.
According to the report, fish and algae became concentrated in the upper layer, then sudden reductions in air temperature and increased wind associated with storms caused the layers to mix, resulting in low oxygen throughout the water and no escape for the fish.
In a statement, the Australian Academy of Science (AAS), which released its own report into the fish kills earlier this week, described the assessment as “a welcome contribution to the growing evidence base to help inform action to improve the health of Australia’s rivers”.
“Decisions to maintain and improve Australia’s river system based on the best available science are something all Australians want to see,” according to the AAS statement.
Report does not asses the cause of long-term declines in flow
The response noted, however, that the government report does not yet directly assess the cause of long-term declines in flows into the Darling River.
This is something the AAS outlined in its own report, which was commissioned by opposition leader Bill Shorten and compiled by a multidisciplinary expert panel.
The Panel Chair, Professor Craig Moritz from the Australian National University, told journalists at an AusSMC briefing that the kills are an indicator of a system in crisis.
“These kills are unusual in their severity [and] their connection to poor, still water with algal blooms,” he said.
“We’ve known for some time that the river is in crisis.”
Climate change not factored for in plan
The AusSMC also gathered independent expert comments on the new government report.
Macquarie University’s Associate Professor Culum Brown told the Centre the report singled out extreme weather conditions as a major factor responsible for the fish kill.
“Frankly this is nonsense,” he said.
“If they had factored climate change into the basin plan, as any sensible manager would do, they would have anticipated these extreme events and increased environmental water allocations accordingly.”
“What’s more, these extremely hot days will increase in frequency in future and will soon be the norm.”
Professor John Quiggin from the University of Queensland agreed that the conditions which made the Darling so vulnerable were worsened by “policy failures of the current government”.
These failures included “upstream extractive use of water, the decision to release water from Menindee Lakes in 2016, and the extreme climatic conditions which are the ‘new normal’ as a result of climate change”, he said.
Prof Quiggin told the AusSMC that the statement released by the Federal Minister for Agriculture and Water Resources David Littleproud ignores all these factors, focusing only on the immediate causes of the disaster.
But the AAS is hopeful that a collaborative approach between the Federal Government and independent scientists is achievable.
The AAS report earlier this week featured 20 recommendations to improve freshwater systems in the long-term, including improved water monitoring, increased local community engagement and factoring climate change into water management.