Thousands of dead, dead fish have already been found on the riverbanks as the extent of Cyclone Alfred’s influence on marine life begins to become clear.
As northeastern Australia begins to recover from Cyclone Alfred, thousands of fish have either died or died on the banks of the Richmond River in Ballina, Northern New South Wales (NSW), according to Charity Ozfish.
They are currently seeking help from public members to track the extent of fish killings in areas that were heavily hit by weather events that crossed the coast a week ago, causing widespread flooding in the area and in the southeast Queensland.
Locals have been warned to brace for the killing of more fish, and a NSW government fisheries spokesperson said an investigation into the report is ongoing.
“Fishing staff have contacted local councils about water quality and fish death monitoring, and several locations have been affected,” they said. “Ongoing fish killings in the area are expected next week in the coming days.”
Ozfish wants to allow locals to record and report dead fish, leaving them dead, so that they can understand the scale of their deaths.
Its CEO, Kathy Price, said it is likely that the cause is black water, which contains very low oxygen levels.
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When organic matter such as dirt and leaf shapes are washed away into the waterway, they turn darker and removes oxygen water as they decompose.
Courtesy of Ozfish
Photos provided by the charity appear to show fish washed away on the riverbanks, but say they have also received reports of mud crabs and eels coming out of the water to escape contamination.
Price said the results of the water tests conducted by the volunteers were “not good.”
“Healthy water requires at least 5 milligrams (mg) of oxygen per liter,” she said. “Fishes experience pain when they start dying at less than 4 mg per liter at 2 mg. Today, on the Richmond River, dissolved oxygen levels are almost zero, sitting at 0.4 mg.”
People can help oz crabs by recording pin drops, globe references to their locations, estimate the number of fish, take notes on important species that can be identified, and take photos and videos.
Dozens of fish murders are reported in NSW each year, but some events are more devastating than others.
An estimated 20 million fish were killed in flooding on the Darling River in Mendy in March 2023. And earlier this year, the ocean heat wave was thought to have been found to have killed about 30,000 fish at Gunoarea Beach near Karata on Western Australia’s Pilbara coast.
Price said restoring the swamps around the Richmond River will help prevent similar events in the future.
“We need to take urgent action to prevent further fish killing and build resilience in the waterway,” she said.
AAP contributed to this story.
