Mass fish kill chokes waterways in Byron region

March 24, 2025 journo

Thousands of flathead, bream, whiting and schooling prawns have died in a devastating fish kill in the aftermath of Tropical Cyclone Alfred, choking the waterways of coastal and riverside towns in Northern NSW.

Residents spared from the worst effects of Alfred say the catastrophe has now arrived as the fish die gasping in blackwater starved of oxygen. Locals also reported eels and mud crabs crawling out of de-oxygenated water and dying on the shore.

Thousands of dead fish littered the canals of Ballina due to oxygen-starved blackwater.Credit: Danielle Smith

“We’ve lived here for five years, and during this time, we’ve had a flood, we’ve had a cyclone and a fish kill,” Lucy van der Hoeven, who lives on a canal in Ballina, a coastal town at the end of the Richmond River, said.

“The flood was tough, but this would have to be the toughest … to see all that death and sadness. I mean, just to see that this beautiful, beautiful fish die, it’s killing us.”

The fish are suffocating in water contaminated by the floods, with rotting plant material washed into rivers and creeks by the relentless rainfall summoned by Cyclone Alfred earlier this month.

Locals have mobilised to help clean up the piles of decaying fish, while the stench of blackwater and rotting fish leaches into homes via drainpipes.

Joshua McPherson from Lismore council helping clean up the fish kill in Ballina.Credit: Danielle Smith

Lismore council worker Joshua McPherson headed to Ballina over the weekend to lend a hand. He said council workers and residents disposed of four tonnes of fish on Saturday morning.

“And that wasn’t all of them. There were plenty on the bank, a lot in the water.”

Ballina local Wendy Sharpe said the scale of the devastation was heading toward the same level of the area’s worst fish kill about 10 years ago. She’s been cleaning up dead fish every day for a week – including about two or three thousand on Saturday morning.

“I think that picking up fish early is making a difference,” she said. “You can’t be inside and have your doors open because the air is so ripe.”

Locals Wendy Sharpe and Les Clarke said they’d cleaned up between two and three thousand fish in one morning.Credit: Danielle Smith

Mass fish kills have struck in the West Ballina canals, Ballina’s riverbanks, Gawandii Beach and Shaws Bay, according to the local council.

Reports of dead fish began last Monday, according to OzFish. “Healthy water should have at least 5mg of oxygen per litre,” the organisation’s chief executive Cassie Price said. “Fish experience distress when it falls below 4mg per litre, and start to die at 2mg a litre.”

Readings from last week found levels as low as 0.4mg and some monitoring had come back with oxygen levels of nil.

The charity argues restoring the 6000-hectare Tuckean Swamp, one of the largest wetlands in NSW that lies around the Richmond River, would slash mass mortality events after extreme rainfall.

“Healthy swamp bordering rivers acts as a sieve, or a filter, that reduces the blackwater from entering the waterway,” Price said.

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