The Badenoch and Strathspey Conservation Group (BSCG) has released a report by the James Hutton Institute, released under a freedom of information act request, that suggests there has been a 50% decline in Freshwater pearl mussels in the River Spey over the last 15 years.

The report says scientists had identified pollutants, such as high levels of phosphorus from detergents, fertilisers and human waste, as being the cause of the harm, with the worse affected area being in the vicinity of Aviemore.

BSCG are concerned that the proposed building of thousands more homes in the Cairngorms will put the rare species at greater risk.

Dr Gus Jones Convener of the Badenoch and Strathspey Conservation Group (BSCG) said: "It looks alarmingly as if the Spey’s pearl mussels are in free fall. If pearl mussels are to have a future in the Spey it is vital that current pollution standards are improved immediately. We hope this timely report will be a wake up call that radical action is urgently needed if Scotland is to save the Spey’s pearl mussels. The report reveals that pollution levels are already exceeding safe limits and yet thousands more houses are planned in Strathspey, further impacting on water quality."

Roy Turnbull (Vice convener) of Badenoch and Strathspey Conservation Group added: "The pearl mussel decline follows the building of about three thousand houses in Strathspey in the last thirty years. Yet the national park plans to allow thousands more houses, which would increase the pollution of the Spey."