Compliance Manager Tami Sargeant said the ORC’s pollution team responded to a report from the public about the fish kill and found 130 to 150 deceased brown trout and one other fish believed to be a galaxiid.  The cause of the fish kill could not be identified.

Ms Sargeant said water samples were taken and autopsies of some fish are underway, with ORC now awaiting results.

“Without enough information we can’t conclusively say what led to the fish kill but there are some potential scenarios that could have caused this– including a chemical discharge into the stream.

“Regardless of the cause, anything that can cause this scale of death will be unpleasant for the animals concerned.”

She says that one possibility is that a contaminant has entered a stormwater drain that discharges directly into the creek further upstream.

“If anyone from the public has seen anything in relation to this or any other behaviour that may have led to the deaths surrounding the Horn Creek area, we would greatly appreciate them getting in touch with us on the Pollution Hotline on 0800 800 033 so we can get to the bottom of what happened to these fish. Information can be provided anonymously.”

“This is a significant event and most likely preventable. As well as confirming the cause, we want to raise awareness and make sure behaviour does not contribute to the degradation of our waterways, and that we prevent more deaths of fish species of this scale in the future.” said Ms Sargeant.

She says most stormwater is not treated before it drains into local waterways, so anything that goes down the drain could likely end up going directly into a waterway and harming that ecosystem.  

“This is a timely reminder for everyone to be more care careful about what goes down our stormwater drains. Best case scenario is that only rain goes down the stormwater drains. Our team have resources on our website and can provide advice for industry stormwater pollution prevention.”

Depending on the chemical, there is a range of solutions available to dispose of any waste appropriately, and ORC encourages people to contact their local TLA for advice on the appropriate disposal method.

You can find more information on ORC’s website here.