Monitoring Salmon Escape Impacts: New River Lochy–Mowi Study

The River Lochy Association and Mowi Scotland have embarked on a significant long-term scientific study to assess the effects of a recent salmon escape at Mowi’s Gorsten farm in Upper Loch Linnhe. This initiative follows an incident on October 5, 2025, when approximately 75,000 sexually immature salmon escaped due to extreme weather conditions associated with Storm Amy.

This collaborative effort, primarily funded by Mowi, will leverage the genetic expertise of the Institute for Biodiversity and Freshwater Conservation at UHI Inverness. The study aims to monitor the potential impact on salmonid populations in the region and implement necessary mitigation measures.

Immediate Actions Taken

In light of the escape event, Mowi, in coordination with the River Lochy Association, executed several immediate actions:

• Recapture Efforts: Given the timing of the escape close to spawning season, nets were not used; instead, rod-catch methods were employed.
• Angler Deployment: Over 100 anglers were mobilized across the region, and all captures were tracked using the Fisheries Management Scotland escapes reporting app. To date, 440 fish have been reported caught, mostly in the lower sections of the Lochy and Leven rivers.

Long-Term Study Framework

The detailed scope of the long-term study includes the following components:

• Genetic Screening: Scale samples will be collected from returning adult salmon in 2026 and 2027 to evaluate the presence of farmed fish genetics from the escape.
• Electro-fishing Surveys: Local fisheries biologists will conduct surveys in all major salmon catchments in the Upper Linnhe region, collecting fry samples for genetic assessment to establish baseline data.
• Follow-Up Sampling: The fry sampling will be repeated in 2027 and 2028 to assess any genetic impacts in the wild salmon population resulting from the escape.

Expert Opinions on the Study

Jon Gibb, Manager of the River Lochy Association and Director of the Lochaber District Salmon Fishery Board, expressed confidence in the collaborative approach:

“An escape of farmed salmon into the wild is something that nobody wants to see. However, I am optimistic that our comprehensive three-year genetic monitoring plan will effectively determine any impact on the local wild salmon population.”

Stephen MacIntyre, Head of Environment at Mowi Scotland, remarked on the company’s commitment:

“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. This scientific approach will help us understand if there are any genetic changes in the wild salmon resulting from this incident.”

Image Credit: River Lochy Association and Mowi Scotland