River Teifi water pollution kills 1,000 fish after spill
At least 1,000 fish have been killed following pollution of the River Teifi in Ceredigion, Natural Resources Wales has said.
Environmental officers said the water has been discoloured and believe the source was an agricultural site in the Tregaron area.
Salmon and sea trout are among the dead fish and NRW said the number was "rising".
Control measures have been put in place to stop the pollution spreading.
The pollution was first reported on Saturday, with work ongoing to assess its extent.
The group Sea Trout Wales said salmon and sea trout were "already at critically low levels" in the river.
"Sea trout, salmon and brown trout have been spawning in recent weeks and given the nature of the pollution it is very likely that much of this spawning downriver will now be unsuccessful," it said in a statement.
"An incident of this magnitude may see the river take as long as fifteen years to recover, if it actually recovers at all."
Secretary of Tregaron Anglers, Cheryl Bulman, said it was not only "devastating" for the club but the wider community, as "angling brings in big tourism" to the area.
"These sort of things happen and have a long-term effect. It's going go be devastating for a long time to come," she said.
Gavin Bown, south west duty manager for NRW, said: "The pollution incident on the River Teifi near Tregaron has had a significant impact on a large stretch of the river downstream.
"As our officers continue to assess the full impact on the river, the number of dead fish discovered is rising.
"The pollution control measures remain in place and we're investigating the cause of the incident to ensure that no more pollution will enter the river."