§ Viscount Thursoasked Her Majesty's Government:
What research is currently being undertaken into the effects of acid rain and afforestation on Scottish salmon rivers and whether such research demonstrates the view, widely held by district fishery boards and fishery managers, that many important spawning areas throughout Scotland have been rendered sterile by these factors.
§ The Earl of MansfieldStudies of the effect of acidification and afforestation on Scottish freshwater systems are being carried out by scientists of my department, in consultation with the Forestry Commission. The major Scottish salmon rivers lie in Eastern Scotland where the underlying geology is such that a major impact by acid rain is less likely. Nevertheless, I am concerned that there is some evidence of surface water acidification in the area of headwater streams in the Dee and Spey catchment areas. It is recognised that salmonid fish are vulnerable to high concentrations of acidity and aluminium, particularly at the hatching and fry stages, and waters which frequently or continually have high acid levels are unlikely to support self-generating fish populations.
My department's studies will be continued but, as most countries in the northern hemisphere are now subjected to acid precipitation, resulting primarily from industrial emissions, a long-term solution could only be provided by worldwide action.