Thousands of dead fish wash up on Sydney’s Parramatta River

Authorities have launched an investigation after Sydney residents witnessed thousands of fish dying in a horrifying mass killing event.

Residents have been left horrified after witnessing thousands of fish dying along Sydney’s Parramatta River.

Hundreds of dead fish mixed in with mounds of rubbish have washed up on the banks of the Parramatta River, prompting an investigation from NSW’s Environment Protection Authority (EPA).

Concerned locals have been posting images of the mass fish death to social media, with dead fish washing up along the river from Rhodes, all the way to Rydalmere.

One local man posted a video to YouTube on the Channel Windsor Bait and Tackle earlier this week, revealing he had witnessed the fish dying right in front of him.

Stream more environmental news with Flash, a dedicated news streaming service. New to Flash? Try 14 days free now >

The local said he witnessed the fish dying before his eyes. Picture: Windsor Bait and Tackle/YouTube

He said there were thousands of dead fish. Picture: Windsor Bait and Tackle/YouTube

“I just witnessed a massive fish kill. I knew there was something wrong. I could tell from the start when I started fishing that there was something wrong,” the man said in the video.

“Later on I started catching prawns by hand. When prawns come up like that you know there’s something wrong.

“I started to look more and more, all of a sudden I started seeing all these dead fish and the fish were dying in front of my very eyes, they were rolling up on the bank. I pushed a few back in but there were thousands and thousands of dead fish.”

He described the situation as “horrifying”, revealing he had been left stinking like dead fish.

Rubbish and dead fish have washed ashore in Rydalmere in Sydney’s west. Picture: Kellie Darley

Another resident, Kellie Darley, posted pictures of masses of dead fish mixed in with rubbish along the river bank in Rydalmere.

“I came down to see for myself and the whole thing is made even worse by the large amount of rubbish along this stretch – hard to tell the dead fish among all the litter … But they are there in large numbers sadly,” Ms Darley posted in a local Facebook group.

“I understand a number of residents have reported it and I will also. Would be useful to know what has caused the mass fish kill. I’m also raising it with Council.”

On Tuesday, the NSW EPA announced it was investigating two separate fish kill events, one reported at Haslams Creek last Thursday and one reported on Monday along the Parramatta River at Rydalmere.

Investigations have indicated that the fish kills were the result of low dissolved oxygen in the water.

Dead fish have also been seen on the Rhodes foreshore. Picture: Jennifer Dixon

“Preliminary investigations indicate low oxygen levels were most likely due to natural causes, the EPA said of the Parramatta River event.

“Observations by EPA Officers indicate low oxygen levels were caused by high intensity storms that washed organic matter into the waterway, which combined with elevated water temperatures, has caused the fish deaths.”

While it was difficult to gain exact numbers, authorities believe up to 4000 fish may have died in the mass kill event.

The EPA is working with the Parramatta Council to clean up the banks and remove the fish where possible.

Authorities believe the low oxygen levels at Haslams Creek were not caused by chemical pollution and were likely from natural causes.

Water quality monitoring at Haslams Creek have shown that oxygen levels have since returned to normal.

It is estimated a few thousands fish and prawns died as a result of the event.

“It is distressing to see a significant number of fish killed and a variety of species impacted,” the EPA said.