An investigation has started into a pollution incident which killed thousands of crayfish at a beauty spot.
The exact nature of the pollution is still not clear
The Environment Agency was alerted on Sunday after a member of the public saw a number of crayfish in the River Mint at Patton Bridge, north east of Kendal.
Officers found large numbers of native white-clawed crayfish had been killed or were in distress.
Exact figures have not been confirmed, but it is expected the number killed is likely to be thousands.
The Environment Agency said initial investigations confirmed the crayfish had been killed by a pollutant entering the water, but the exact nature is still unclear.
A 10km stretch of the river is believed to have been affected by the incident and Agency officers are still checking whether the pollutant has affected the neighbouring River Kent.
They are also trying to find out whether any other fish species have been affected and trying to find a possible source for the pollutant.
Agency fisheries technical officer for Cumbria Graeme McKee said: "White-clawed crayfish are the only native crayfish species and we expect this loss to have a significant impact on other creatures locally such as otters, who rely on crayfish as a key food source.
"The pollution has affected the entire river and clearly our key concern at this stage is to minimise any further impact, particularly into the nearby River Kent."