An investigation is under way after trout were found dead in a creek near Arrowtown.
The Otago Regional Council is investigating after a number of brown trout were found dead in Mill Creek several days ago.
ORC chief executive Peter Bodeker said in a statement there were no obvious signs as to what had caused the deaths.
''There is no construction site nearby and no signs of the sort of land disturbance or other activity that might generate pollutants.
''We are keeping an open mind about the cause at this stage and not ruling anything in or out. We are very keen to hear from anyone who has noticed any unusual activity along Mill Creek in the Speargrass Flat area.”
ORC staff have collected water samples at several points along the creek, upstream and downstream of where the fish were found.
The samples are being analysed to establish the presence of pesticides or other chemicals and heavy metals, as well as the overall quality of water in the creek and an adjacent wetland.
Results are expected within a week.
Two of the dead fish have been sent to the Cawthron Institute in Nelson for autopsy, and those results were expected in about a fortnight.
Mr Bodeker said calling the ORC’s 24-hour pollution hotline 0800 800 033 was the easiest way for people to report water quality issues anywhere in Otago.
ORC already monitors water quality in Mill Creek regularly as one of the significant tributaries to Lake Hayes, as well as the lake itself.
