The Richmond River catchment is the sixth largest in New South Wales and covers an area of nearly 7,000 square kilometres in the north of the state.
It was once a thriving, heavily timbered forest, but since European settlement it has changed dramatically.
The banks of the river are now home to intensive agriculture, grazing, and urban development, which Rous County Council chairman Keith Williams said had long been blamed for killing the river.
“We all thought the river was bad five to 10 years ago,” he said.
“But when all the oysters at the mouth of the river died, the entire estuary — hundreds and thousands of oysters — they just died all at once.
“It’s like a slap in the face and you suddenly realise, this water and the river is not fit for marine creatures to live in anymore. So there’s got to be something majorly wrong.”
Coral tree poisoning, Wilson Creek.