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Millions of dead fish are clogging a river in south-east Australia, angering locals who have to endure the smell of decaying carcasses that has blanketed the water for days. Officials say this is due to a lack of oxygen brought on by rising temperatures and recent flooding, while residents blame the government for water mismanagement.
“There’s dead fish everywhere,” said Graeme McCrabb, a Menindee resident, on Sunday, describing the smell in NSW’s Darling-Baaka River as far-reaching and pungent. Among the dead fish are native species such as bone bream, Murray cod, gilthead, silverfish and carp, he said.
A video he took from his boat showed a thick carpet of silver fish carcasses on the water.
Australian officials have been aware of the disaster since Friday, acknowledging “an evolving large-scale fish kill” involving millions of carcasses in the river. The New South Wales Department of Primary Industries (DPI) blamed low oxygen levels in the water, known as hypoxia, for the flood waters receding.
“The current hot weather in the region is also exacerbating hypoxia, as warmer water contains less oxygen than cold water and fish have higher oxygen needs in warmer temperatures,” the agency said in a statement on Friday.
McCrabb said the same remote area did recorded large-scale fish kills in December 2018 and January 2019, citing it as the result of poor-quality water entering the river, which is commonly used for fishing. But this time, McCrabb said, the disaster was far worse, and many in the city were “angry and disappointed” that officials appeared to have learned nothing from previous mass fish die-offs.
“Nobody was ready for what was seen here,” McCrabb said, adding that officials “failed in their duty” to manage the river and collect data to prevent such disasters.
“If you know the water quality is good or bad, you can make more informed decisions about how water is released downstream from the lakes and avoid sending blackwater downstream to kill fish,” McCrabb said.
Blackwater events “occur during floods, when organic matter from the river bank and floodplain is washed into the river system,” according to the New South Wales Department of Water.
The government said the dead fish were mostly bone herring, a species that is booming and busting in numbers.
“During times of flooding, population booms and can then suffer significant deaths or ‘bankruptcies’ as rivers return to more normal levels,” DPI Fisheries called. “They may also be more vulnerable to environmental stresses such as low oxygen levels, particularly under extreme conditions such as elevated temperatures that are currently affecting the region.”
Cameron Lay, director of freshwater environments at DPI Fisheries, described the situation as “very concerning” and warned that temperatures in excess of 100 degrees in the region could pose further challenges.
“That in itself can pose an ongoing risk to water quality and local fish, so we will do everything we can to monitor the situation and use all management options at our disposal,” he said, according to the Australian Broadcasting Corp.
Accelerating climate change is warming the water and boiling creatures in their own habitats, experts say. Many species suffocate because warmer water cannot hold as much dissolved oxygen.
A study published last year found that if greenhouse gas emissions continued to rise, about a third of all marine life could disappear within 300 years.
Marine animals are at risk of mass extinction due to climate change, a study has found
The remote site of the recent fish kill in far western New South Wales only makes the disaster worse. The crumbling fish blanket has been visible for at least three days. “It’s difficult to get people here in a hurry,” McCrabb said. “If you try to pick [the fish] You will likely break them and leave a chowder of fish. There aren’t really many answers.”
Several agencies are working on a response to the disaster, the New South Wales DPI said.
The NSW Department for Planning and Environment’s water department confirmed “a large number of fish kills” and called “Dissolved oxygen levels remain a concern for fish health.”
“The reality is that the Darling River is very sick. Years of mismanagement by the NSW government have exacerbated the impact of our changing climate,” said Rose Jackson, NSW MP and Shadow Secretary of State for Water and Housing. wrote on Twitter. The ecosystem “has been brought to the breaking point.”
On Sunday, McCrabb said fish continue to die in the water – adding to the already monumental loss of aquatic life. “We started losing more this afternoon,” he said, noting that some of the dead mass was beginning to move downstream.
He said more deaths along the river were likely in the coming days: “We are in a world of injuries here.”
Sarah Kaplan contributed to this report.