Water temperatures as high as 21°C have been recorded on the upper river Dee this month, in what could well be a record-breaking month, threatening the river’s wildlife.

Staff from the River Dee Trust conservation charity record water temperatures on the Dee to monitor the health of the river ecosystem and contribute to the wider study of river temperatures across Scotland through the Scotland River Temperature Monitoring Network (SRTMN).

The Trust’s biologist, Dr Al Reeve explains:

“This month we’ve recorded temperatures in hill tributaries of the Dee used as nursery areas for young fish of 20°C on the Geldie Burn, up in the eastern Cairngorms and of 21°C on the Gairn, nearer Ballater. Even more worrying, these highs have hit two weeks earlier than in 2023.

“Our keystone species, the Atlantic salmon, is adapted to live in cool environments with an optimal temperature range of 16-17°C for growth. Beyond this range, the fish stop eating, display behavioural changes and stress. There is also a negative impact on the river’s invertebrates and consequently, on other wildlife too.”

The River Dee Trust is behind a number of transformational habitat restoration projects, including the award-winning One Million Trees campaign, and the 20-year Save the Spring project – designed to deliver riverside woodland creation, peatland and wetland restoration, as well as re-naturalising the river channels. These efforts will help to reduce temperatures, control the flow of water off the land during flood events and provide young salmon shelter from predators, extreme heat and the effects of climate change, while improving the wider biodiversity.

More recently, the Trust has launched the River Dee Guardian scheme designed to engage the business community in the restoration of the river.

Claire Fleming, Engagement & Fundraising Officer at the Dee comments:

“By becoming a River Dee Guardian, businesses and individuals are demonstrating their commitment to the future, and Guardians have been active in volunteering activities including tree planting as part of our efforts to provide vital shade to help keep the river cool.

“There is a lot of work to be done and the support of the business community is vital to enable the restoration to take place at a landscape scale to benefit threatened wildlife.”