Claire Corlett

Fish Food, Fish Tanks, and More
Investigation of the causes of mass fish kills

Investigation of the causes of mass fish kills

They were the grim scenes that shocked Australia
and made headlines around the world. Millions of fish found dead in western
New South Wales. “To me, it was like the coral bleaching moment for the inland. It was an incredible wake-up call.” There were three separate fish kills that took place in rapid succession. The first happened on December 15 last year along a 30-kilometre stretch of the Darling River, near the town of Menindee. Then on January 6 this year, a larger fish kill was reported along the same stretch of river. That was soon followed by a third event on January 28, again impacting hundreds of thousands of fish including substantial numbers of threatened species: the silver perch and the Murray cod. “You can’t hide. You can’t deny it. This is a disaster. It’s a natural disaster. It’s a national disaster.” The Australian Academy of Science was asked to investigate the cause of that disaster. Panel chair, Professor Craig Moritz, and panel member, Professor Sue Jackson, travelled to Menindee to hear from locals. While there on February 1, they saw for themselves, large Murray cod in dire condition. “Very moving and affecting to actually be there, watching these huge cod, trying to do anything they could to get out of this pool. It was terribly upsetting.” The expert panel determined the immediate cause of the fish kills was insufficient oxygen. Here’s how it unfolded. A layer of warm water had formed over deep, colder water. The upper layer was more oxygenated, largely because of oxygen-producing blue-green algae. Algae flourish in warm and still conditions, particularly when the river isn’t flowing. But as algae die, they sink to the bottom, feeding microorganisms that use up dissolved oxygen. When a cool change hit the region, it mixed the smaller top layer with the larger, lower body of water. As that happened, the crucial oxygen from the top warm layer became diluted and was quickly used up. Not enough was left for the fish. Large temperature fluctuations coincided with all three fish kills. But while that was the immediate cause, it doesn’t get to the root of the problem. “The recent fish kills are certainly related to water management issues.” The panel found there isn’t enough water in the Darling system to avoid catastrophic outcomes. This is partly due to the ongoing drought. However, decades of rainfall and river flow data point to excess water extraction upstream. That’s a finding welcomed by local Indigenous elders, who have long argued that the system is being mismanaged. “We’re stuck in Menindee with the fish dying. The kids are getting sores all over them. And we’ve got no water, just about. So, where’s the water sharing plan? It’s not worth the paper it’s written on because they’re not listening to local people.” The expert panel recommends that urgent steps be taken within six months to improve the quality of water throughout the Darling River. That should include the formation of a Menindee Lakes restoration project to determine sustainable management of the lakes system and lower Darling and Darling Anabranch. It also involves improving meaningful engagement with river-based communities, including Indigenous peoples. Beyond that, the panel recommends a return to the intent of the 2012 Murray Darling Basin Plan to improve environmental outcomes. “So the best possible scenario is water in the Darling all the way to the bottom.”

10 comments on “Investigation of the causes of mass fish kills

  1. Great explainer video. Outrageous that it takes this kind of disaster to (hopefully) spur our political leaders into actually solving this problem.

  2. Very well done, this all fell together so beautifully at the end! The time and energy you put into putting this exceptional work of art together was well worth it! Thank you so much, can not wait until your next adventure!

  3. If this vid is a reflection of the investigation to this matter then pathetic, there wasn't one. Theres no mention of names . politicians or their buddies they helped run the river dry with those huge pipes that were illegaly setup. No one is going to be prosecuted or go to prison over this serious crime. They didn't even mention why the weather is now so haywire , it's called  >  Geo Engineering < . Instead the soldout Hi – Jacked  Government go to great lengths to censor & cover up truth on this matter. With planes they spraying amounts from 20,000 to 100,000 tons worldwide toxic poisons to terraform the planet is pure madness.Down here in Victoria 6 or 7 months ago the Vic Gov were taken to court & found guilty of criminally destroying old growth forests in Gippsland for their own filthy greedy profit into their own pockets selling it of to Bunnings & Officeworks.  Back then a plan was to be written up to enforce it & guess what? The court didn't even bother to do it cause there as corrupt to da core as the gov are, none of them go to prison over this shit. So the criminal Vic Gov even now are still at it in their destruction to chop it all down as fast as they can. The Government don't give a rats arse about any of this period. With 90% of all reefs worldwide now dead & the government are still pushing hard to try get Adani happening with the Carmichael Coal Mine in Qld with their is it 68 years to take as much water as they can to poison it all & wipe out The Great Barrier Reef. The Artic & Canandian Permafrosts are now thawed out for no more ice or cold while here in AUstralia theres nothing  normal about our weather as it's man made manipulated / controlled.  In around 6 years time 2025 the O – Zone Layer is expected for final total collapse  & will result in most vegetation die of that will result in mass crop failure. To blame this fish cull on drought is BS & will they implement this 2012 Murray Darling Plan? I doubt it. Well now we have Chinesse MIllitary Launch Pad Bases in WA is quite obvious were being setup big time. It's just a pitty theres not many people awake to all as just how bad things really are. To all you caring, passionate Aussies , stop taking this up the arse & start paying attention to educate yourselves on these matters.

  4. Somebody has to do some phony platitudes to explain this. A worldwide problem due to real change, not spare change we are faced with….Gaia in action

  5. All of the rivers and creeks in Australia are full of silt and other debris, and there is very little room left for the water. The holes are filled up through human activities. What we put in, we can take back out again, we would be simply taking out the trash. This is a task that demands a sensitive and pains-taking love of the riparian zones of the planet. Our rivers could have ten times more water in them. The catchments need to be protected by forests and by vegetative cover. The silt is very fertile, and there are many useful materials just right for repairing and reinforcing the channels and doing sensitive remedial work. The riparian network is the most perfect water storage system, it needs to be redeemed with great affection and respect. We could make great environmental progress with abundant fresh water.

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