Investigations have been launched after dozens of fish were killed after a leak polluted a Moray burn.
Passers-by reported the cloudy “noxious” substance entering the water near a fish ladder at Sanquhar Loch in Forres.
Witnesses reported fish being killed “instantly” after coming into contact with the substance.
Yesterday the cause of the leak into the Mosset Burn remained unknown with an investigation underway by Scottish Water to examine the source.
Crews from Scottish Water attended after the pollution was reported on Tuesday, further checks yesterday confirmed there had been no further spill.
Officials entered the water themselves to retrieve the fish, which have been sent for analysis to determine the cause of death.
Bob Laughton, biologist and director of the Findhorn, Nairn and Lossie Fisheries Trust, estimated that up to 30 trout had been killed by the spillage.
He said: “It’s difficult to say what’s happened. It came from a storm drain at the top of the fish ladder to allow fish to pass through the Sanquhar dam.
“Some of the noxious substance came through, possibly through sewage of some form of run-off, I don’t know.
“Thankfully these sorts of things are very rare these days, most systems work pretty well and you only occasionally get something like this. This was pretty minor anyway.”
The pollution was reported to environmental agencies for investigations to begin.
A Scottish Water spokeswoman said: “Following reports of a pollutant entering the Mosset Burn on Tuesday, we attended at the site.
“Checks were carried out and no issues were identified with the Scottish Water network. Our trade effluent team is currently working to identify the source and Sepa has been informed.
“There did not appear to be any further pollutant entering the burn on Wednesday.”
A Sepa spokesman said: “We were informed on Tuesday of sewage being discharged from a pipe on a nearby road into a fish ladder which leads to Mosset Burn. Scottish Water is currently investigating.”