Atlantic salmon have been recorded further upstream on the River Teign in Devon following more than a decade of targeted habitat restoration work led by South West Water and conservation partners.
Electric-fishing surveys show salmon are now consistently present in the upper reaches of the South Teign, where they had not been observed for many years. Monitoring has recorded salmon at a site close to the Fernworthy Reservoir dam wall for five consecutive years, with salmon fry also found in the area, providing clear evidence that spawning is now taking place upstream.
The work forms part of a long-term programme to address the impact of reservoirs on natural river processes, particularly sediment movement critical to fish reproduction.
Rebuilding spawning habitat
Over an 11-year period, approximately 1,000 tonnes of carefully selected gravel have been added to the river to recreate the loose, clean riverbed conditions required by salmon and trout to lay their eggs. Dams and reservoirs interrupt the natural downstream movement of sediment, often leaving riverbeds compacted and unsuitable for spawning.
“We are effectively rebuilding the riverbed,” said Olivia Cresswell, Head of Fisheries and Ecology at the Westcountry Rivers Trust.
“Dams and reservoirs reduce the natural supply of gravel and stones to downstream spawning grounds. On the upper Teign, after 11 years of adding nearly 1,000 tonnes of selected gravel, we’ve brought the habitat back to something very close to pre-reservoir conditions. It’s so rewarding to see.”
Monitoring by the Trust indicates that salmon are actively using the newly formed spawning beds. Strong numbers of brown trout have also been recorded, suggesting wider ecological benefits from the restoration work.
A threatened species
The findings come at a critical time for Atlantic salmon, which are now considered one of the UK’s most threatened freshwater species. Salmon numbers nationally have fallen to record lows, with some rivers in the South West seeing fewer than 60 adult fish return each year.
Dartmoor rivers are particularly vulnerable to climate pressures. Hotter, drier summers reduce river flows and increase water temperatures, both of which place additional stress on salmon. Invasive species, sediment build-up, fragmented habitats and aquatic weed growth further limit spawning success.
The River Teign results demonstrate that targeted, long-term habitat restoration can deliver measurable improvements even in heavily modified river systems.
Balancing water supply and conservation
Unlike many other regions of the UK, Devon and Cornwall rely heavily on surface water rather than groundwater to meet public water demand. Steep, rainfall-dependent rivers can fluctuate rapidly, making reservoirs essential for maintaining reliable year-round supply.
South West Water has integrated fisheries expertise into its Water Resources division to ensure ecological considerations are embedded in operational decision-making.
Dr Georgina Samoluk, Fisheries and Biodiversity Advisor at South West Water, said the company’s mitigation work at Fernworthy and other sites across the region remains essential.
“None of the 16 Principal Salmon Rivers in Devon and Cornwall currently support sustainable salmon populations, meaning every step we take is important,” she said. “Managing flows and protecting the fragile ecosystems that salmon rely on are at the heart of our work within the Environment Team.”
She added that the South West’s comparatively mild winters present further challenges, as salmon typically favour cooler water conditions.
“Every salmon that makes the incredible journey upstream is a sign that our rivers can still support this species. However, now more than ever, we must work together – using engineering, science and partnership – to give these iconic fish a real fighting chance.”
