Low oxygen levels in River Spey may have killed fish

Low oxygen levels may have caused the deaths of dozens of salmon and trout in a Scottish river.

It is believed more than 50 adult fish have been found dead over an almost 18-mile (29km) stretch of the Spey since Saturday 9 September.

The Scottish Environment Protection Agency (Sepa) said it had found no evidence of significant pollution.

But it added that low river flows and high temperatures may have resulted in low oxygen in the water.

Spey Fishery Board alerted the authorities after fish were found dead at sites along the river between Grantown-on-Spey in the Highlands and Knockando in Moray.

Pollution has been ruled out because other wildlife, particular insects, appear to have been unaffected.

Sepa said one of its ecologists had carried out a survey and initial findings confirmed insect populations appeared to be normal, indicating there were no water quality issues.

It added: "Any acute significant pollution in the river would also cause mortality in many other species and across the entire size and age range of fish.

"A number of other potential causes are being considered such as low oxygen in the water caused by low flows and high temperatures, as was the case at the time in the river."