Mowi Scotland and the River Lochy Association have agreed a long-term scientific study to assess the impacts of a major salmon escape from Mowi’s Gorsten farm in Upper Loch Linnhe during Storm Amy in October. Funded by Mowi and supported by genetic specialists at the Institute for Biodiversity and Freshwater Conservation at UHI Inverness, the programme aims to monitor and mitigate any adverse effects on wild salmonid populations in the catchment.
On 5 October 2025, an estimated 75,000 sexually immature salmon, with an average weight of 860g and originating from a recirculating aquaculture system (RAS), escaped into the wild following extreme weather conditions. The company anticipates low survival rates in the wild but has moved quickly with local partners to understand any potential long-term consequences.
Immediate response measures focused on recapturing fish that entered nearby and more distant rivers, avoiding the use of nets due to high water levels and the proximity to salmon and trout spawning season. More than 100 anglers were deployed across the region, with 440 immature fish, weighing between 0.5kg and 2.5kg, reported captured so far, most from the lower reaches of the Rivers Lochy and Leven via the Fisheries Management Scotland escapes reporting app.
The new monitoring plan will see scale samples taken from most rod-caught adult salmon in the Lochy and Leven rivers in 2026 and 2027, with genetic screening used to identify any farm-origin fish returning from the ocean. In 2026, fisheries biologists will also carry out timed electro-fishing surveys across all major salmon catchments in the Upper Linnhe area, sampling fry at 58 established sites to create a pre-incident genetic baseline.
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Jon Gibb, Manager of the River Lochy Association and Director of the Lochaber District Salmon Fishery Board, said: “Obviously an escape of farmed salmon into the wild is something that nobody wants to see. But I am confident that between Mowi and the River Lochy Association, the local wild fishery management body, that we have designed a comprehensive three-year genetic monitoring plan that will definitively identify whether there will be any impact whatsoever from this unfortunate incident on the local wild salmon population.”
Stephen MacIntyre, Head of Environment at Mowi Scotland, said: “While we are disappointed this incident occurred, we acknowledge our responsibility to monitor and assess the potential for any adverse impacts on local wild salmon populations. Using this scientific approach, the monitoring study will determine whether there is evidence of any changes in the genetic composition of wild salmon arising from the escape incident. We look forward to supporting the delivery of the study with the River Lochy Association over the next three years.”
These fry surveys will be repeated in 2027 and 2028 to detect any genetic signal from the escape within wild stocks, providing evidence on whether the event has altered the composition of local salmon populations. River Lochy Association manager Jon Gibb described the escape as regrettable but said the jointly designed three-year plan should definitively show whether there is any impact on wild salmon, while Mowi’s head of environment, Stephen MacIntyre, said the company accepts its responsibility to assess and monitor any potential effects.
