Thousands of dead fish and prawns have washed on the banks of a bay in Sydney, Australia in a rare natural phenomenon.
Concerned locals have been posting images of the mass fish deaths to social media, after they began washing up along the banks.
One man even posted a video to YouTube revealing he had witnessed the fish dying right in front of him.
He said in the clip: "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.
“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.”
The fish and prawns were spotted in Haslams Creek flowing into Homebush Bay and thousands more were found dead on the Parramatta River in Rydalmere also in the city.
Experts believe strong storms washed twigs and leaves into river, which combined with water temperatures, had likely triggered a drop in oxygen causing the fish to become starved of oxygen and die.
Environment Protection Authority in New South Wales has said they are thought to have died of natural causes.
The events were likely due to natural causes, the EPA said, with preliminary investigations suggesting Sunday’s fish kill was due to storm runoff.
"Preliminary investigations indicate low oxygen levels were not caused by chemical pollution and were more likely due to natural causes," the EPA said in a statement.
"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," the EPA statement said.
"It is difficult to provide exact numbers but EPA officers estimate a few thousand fish have died, potentially up to 4,000 in the Parramatta River at Rydalmere."
The clean-up is under way but has been hindered by the need to collect the fish without trampling the mangroves.
Officials were collecting water samples and water monitoring was set to continue.
