River managers have stressed the value of using wind-fallen trees in river restoration efforts to save endangered salmon stocks.
The groups of trees, known as Large Woody Structures (LWS) have been used successfully in other parts of the world where fish species face the risk of extinction. They replicate healthy, natural processes where mature trees fall into rivers, adding to vital habitat diversity.
LWS are being used as a restoration tool in a number of rivers across Scotland and are being deployed using methods approved by both Scotland’s nature agency NatureScot and the country’s principal environmental regulator, the Scottish Environment Protection Agency (SEPA). They are expertly designed and installed with all necessary authorisations in place.
The Dee is among many Scottish rivers where LWS are being deployed with significant success as part of ongoing restoration work and research. Responding to concerns raised by an academic about their use, Dr Lorraine Hawkins, Director of the Dee Salmon Fishery Board and Trust, said: "This is a proven method, using natural resources to tackle an urgent issue. We are in a race against time to protect salmon populations, and this is an important tool which will help us. The effects these structures have on river processes provide wide biodiversity benefits and not just a single species.”
Dr Alan Wells, CEO of Fisheries Management Scotland, the body representing the country’s Salmon Fishery Boards and Trusts, said: “Our members are working hard across Scotland to protect and restore river habitats in the face of climate change and increased winter rainfall. The clear advice from the North Atlantic Salmon Conservation Organisation is that fisheries managers should ensure the highest numbers of wild smolts, in the best condition, leave from rivers and near-coastal areas to the ocean. River managers, including those on the River Dee, are therefore exploring a range of interventions to take this forward, and careful monitoring and assessment is an integral part of this work”.
On the Dee, river managers are already seeing fish choosing to spawn in the habitats created by these structures, and adults and juveniles are using the structures as refuge and shelter from predators and heat. Ongoing monitoring is being done with Scottish Government to look further than the immediate benefits. Video evidence has additionally been collected, illustrating early successes (Available to media outlets on request).
Growing trends of sea mortality for Atlantic salmon have exposed weaknesses in our river systems that must be addressed immediately. Salmon evolved as a woodland species, but vast areas of Scotland’s river systems now have no tree cover. Atlantic Salmon were reclassified last year to “endangered" status by the International Union for Conservation of Nature, IUCN. All rivers are affected. In the upper Dee catchment, salmon numbers have reduced by more than 80% since the 1970s.
To find out more about our river restoration projects visit our website - https://riverdee.org.uk/success-stories/