The NSW Environment Protection Authority (EPA) continues to investigate a fish kill event in the Hunter River at Mount Thorley.
Teams of officers have been taking water samples and following up leads in the community each day since the EPA was informed of the fish kill by government agencies on Friday, 20 March.
NSW EPA Director Operations, David Gathercole, said the EPA has directed significant resources to the matter, and water samples are being processed by the laboratory as a high priority.
"Yesterday our officers saw live fish, including juvenile fish fry, swimming in the river and fish that appear to have died last week," Mr Gathercole said.
"This indicates that whatever caused the fish deaths may well have passed.
"There can be many reasons for fish death events, including natural reasons, such as low dissolved oxygen or human causes such as pollution or pesticide spills. Our investigations are continuing into all possibilities.
"We have prioritised water quality testing and will let the community and industry know when water quality is within normal limits.
"We acknowledge the community's concern about this issue and appreciate the help they have provided us. We are following up information from the community. If anyone has evidence they would like to share with us, please send it to our Environment Line via
