A LEADING animal charity has warned about the dangers of Scottish salmon farming following the release of a new study conducted by the Marine Directorate of the Scottish Government.
The newly published research shows that wild Atlantic salmon have been identified as having six times as much farmed genetic material in their DNA compared to fish in areas without aquaculture.
Nick Underdown, Scotland director for WildFish, said: “This latest study is yet more damning evidence that the proliferation of Scottish salmon farms is threatening the long-term survival of our precious wild salmon populations.
“Farmed salmon are selectively bred for rapid growth, so when they escape and interbreed with our wild salmon, the hybridised offspring have reduced genetic fitness to survive in the wild and adapt to environmental change.
“Routine escapes from industrial salmon farms cause irreversible damage to our natural heritage and should be a crime.
“The findings of this study represent a complete failure of successive governments to address the problem of salmon farm escapes and this slow-burn crisis for wild salmon.
“We urge the Scottish Government to halt the expansion of the salmon farming industry, which is currently developing new sites across the country without effective regulation and enforcement.
“It is a shameful irony that the salmon farm industry exports a national image of pristine seas, while the industry itself is contributing to a rapid decline in wild salmon.”
It is the first national study of genetic contamination in wild salmon that documents the scale of the issue, nationally and regionally, with 6639 juvenile wild salmon tested across river sites in Scotland.
It was found that 3.14% of their genome came from farmed salmon instead. This is compared to a lower figure of 0.55% in sites that had no salmon farming.
The charity and study suggest that it is creating an irreversible mark on the native species’ genetic material.
Prevalent contamination was discovered, with farmed salmon DNA shown to be present in one-fifth of the salmon rivers in Scotland. In the river sites documented, this farmed genetic material was found to be present in 39% of samples.
The heart of salmon farming, Lochaber, saw farmed salmon DNA located in 72% of the river network.
The study’s authors state that the scale of the issue is underestimated because it cannot use a pre-aquaculture genetic baseline, as there were no comprehensive studies conducted before the expansion of salmon farming.
This study was based on fish that originated from Norway, as they are noticeably different enough to be properly identified.
The overall wild salmon population is dramatically declining, with a 70% decrease since 2000, falling from 10 million to just three million.
In 2023, wild Atlantic salmon was classified as endangered on the International Union for Conservation of Nature’s Red List of Threatened Species.
Combined with this new study, it has sparked concern as some of the most important spots for wild salmon are being shared with salmon farms.
A Scottish Government spokesperson said: “Salmon farming produces Scotland and the UK’s number one food export, contributing to food security at home and globally.
“Fish farm escapes can have negative effects on wild salmon populations, including inter-breeding (genetic introgression) and competition. This is why Scotland operates a robust regulatory regime.
“Our scientists continue to improve our understanding of the impact of escapes in Scotland and recently published a paper that quantifies levels of introgression at national and regional scales for the first time.
“We welcome the new joint penalties initiative agreed between Fisheries Management Scotland and Salmon Scotland. This recognises our collective commitment to support wild salmon conservation and research where escape incidents occur.
“The Scottish Government is committed to deliver an updated Technical Standard for Scottish Finfish Aquaculture next year, and we will continue to work with the sector to reduce the risk of escapes from fish farms.”
Fisheries Management Scotland and Salmon Scotland, the largest trade body and voice for salmon farming in Scotland, have created an approach that will fund conservation efforts where escapes occur to help support the wild salmon population.
This collaborative effort will be administered by an independent body that will see money raised through escape incidents going directly to local research projects to examine whether they have bred with the wild salmon population.
These fixed penalties and payments will be based on the number of escapees from a salmon farm, ranging from £500 to £50,000.
A Salmon Scotland spokesperson said: “Everyone who cares about wild salmon wants to see their decline reversed, but it is wrong to claim this study proves farm escapes caused the genetic changes found in wild salmon.
“Farm-bred salmon were deliberately stocked into west coast rivers in the 1970s and 1980s, while salmon also naturally move between river systems. There is also no historic genetic baseline for Scotland’s wild salmon.
“The study is a snapshot from one year, so it cannot tell us when those genetic changes occurred or whether they are increasing.
“Escapes today are rare and tightly regulated, and our farmers are committed to preventing them and supporting conservation and genetic monitoring when incidents occur.”
While concerns are mounting, salmon fishing remains an important and vital part of Scotland’s economy.
Salmon is the UK’s leading food export and supports thousands of jobs in rural areas that would otherwise struggle with employment. Scotland has more than 200 active salmon farms, with the sector bringing roughly £1 billion annually to the economy.
An independent report commissioned by AECOM confirmed that salmon farming had a real impact on rural Scottish communities and was a “key anchor” by helping to sustain public services, schools, jobs, local infrastructure and environmental efforts such as contributing to beach cleans on Scottish coastlines.
The AECOM report found that salmon farming provided £784,000 annually to the local communities, and said: “In areas facing depopulation, ageing demographics or economic changes, sustained cultural investment from salmon farmers helps communities maintain identity, confidence and stability.”
