Coorong Southern Lagoon catastrophe worst in decades, says Gary Hera-Singh as hundreds of tonnes of fish perish

A professional South Australian angler says there is one major reason the industry's watching hundreds of tonnes of fish rot.

Gary Hera-Singh said it was one of the worst events in decades. Picture: Ben Clark

More than 200 tonnes of dead fish are estimated to be rotting at the Coorong’s South Lagoon, in what a local fisherman believes to be one of the biggest fish kills in decades.

Yellow-eyed mullet, mulloway and small bream were starved of oxygen when weather events this month stirred up sediment and salinity levels – already several times higher than seawater.

Commercial fisherman Gary Hera-Singh said the event, which lasted 48 hours on June 6-7, had been catastrophic for the industry and the environment.

“With a lot of water shunted around, and because the lagoon is in such poor ecological condition, it created a black ball of gooey mess high in hydrogen sulphide and toxic to fish when it gets into their gills. It kills them almost instantly,” Mr Hera-Singh said.

“We estimated more than the total commercial catch for the whole fishery died in those two days – which is about 200-250 tonnes.”

Dead fish in the Coorong early June 2024. Picture: Supplied

Mr Hera-Singh said it was still too early to determine the impact the kill would have on this year’s catch and the livelihoods of those in the industry.

Mr Hera-Singh attributed the fish kill to the “inability of government departments” and its “upper echelons” for not addressing the “serious ecological issues” that exist.

The federal and state governments committed $70m towards a Healthy Coorong, Healthy Basin Plan from 2019 to 2024 to research ways to restore the Coorong. However, phase two of the plan to examine potential engineered solutions for the South Lagoon was yet to start.

A government spokesman said officers from the Department of Primary Industries and Regions (PIRSA) collected water samples for analysis and did not detect any harmful or toxic algae.

Yellow-eyed mullet, mulloway and small bream were starved of oxygen when weather events earlier this month stirred up sediment and salinity levels – already several times higher than seawater.

Commercial fisherman Gary Hera-Singh said June 6 event, which lasted 48-hours, had been catastrophic for the industry and the environment.

“With a lot of water shunted around, and because the lagoon is in such poor ecological condition, it created a black ball of gooey mess high in hydrogen sulphide and toxic to fish when it gets into their gills. It kills them almost instantly,” Mr Hera-Singh said.

“We estimated more than the total commercial catch for the whole fishery died in those two days – which is about 200-250 tonnes.”

Mr Hera-Singh said it was still too early to determine the impact the kill would have on this year’s catch and the livelihoods of those in the industry.

“A substantial amount (of fishers) leave the industry because of New Zealand fur seals, but the impact of the fish kill on top of that will take some time to play out,” he said.

“There are still some fish around, mostly in the north, the few in the South Lagoon are in poor condition because of the high salt content.”

Mr Hera-Singh attributed the fish kill to the “inability of government departments” and its “upper echelons” for not addressing the “serious ecological issues” that exist.

“Fisheries have worked really hard over the last 20 years to try and provide a fishery for the next generation. But this gives the younger generation no hope,” he said.

The federal and state government committed $70m towards a Healthy Coorong, Healthy Basin Plan from 2019 to 2024 to research ways to restore the Coorong.

However, phase two of the plan to examine potential engineered solutions for the South Lagoon was yet to start.

Greens Senator Sarah Hanson-Young said the fish kill highlighted how badly the Coorong was now struggling. Picture: NCA NewsWire / Martin Ollman

A government spokesman said officers from the Department of Primary Industries and Regions (PIRSA) collected water samples for analysis and did not detect any harmful or toxic algae.

“The State Government again wrote to the Commonwealth a fortnight ago urging it to release the $27.9 million to enable phase two of the plan which will investigate long term engineered solutions to improve water quality in the southern lagoon including a pipeline to the ocean,” the spokesman said.

“Delivering the Murray-Darling Basin Plan, including an additional 450 gigalitre of water for the environment, remains one of the most important ways to improve the health of the river system and the Coorong.”

Greens Senator Sarah Hanson-Young said the mass fish kill was proof there could be no more delays in finalising the plan and the allocated money must be released.

“It’s been a very, very dry few months in South Australia and we know this summer it’s only going to get worse. We can’t afford to see any more delay at helping to save our precious Coorong and the south and north lagoons,” she said.

Barker MP Tony Pasin said the fish kill should serve as a “wake up call” to both levels of government to get on with addressing the hypersaline water in the southern Coorong.

Mr Pasin added it was “extremely disappointing” the state government committed $14m in its recent budget on a bird refuge at Lake Hawdon North “instead of fixing the problem”.