More than one million farmed salmon have died at Mowi Scotland’s facilities, marking the largest mass mortality event in Scotland’s aquaculture sector in a decade.
The incident occurred across two neighbouring locations in Loch Seaforth on the Hebrides, which are recognised as a single farm by the Scottish government.
Mowi Scotland, the UK’s leading salmon supplier to major retailers such as Tesco, Asda, Sainsbury’s, and Ocado, confirmed that the death toll reached 1.05 million fish.
The fatalities took place during the typical 18-month cycle required to rear salmon in seawater, beginning in the spring of 2023.
Ben Hadfield, chief operating officer of Mowi Scotland, attributed the mass deaths to an extraordinary increase in sea temperatures, which led to jellyfish blooms.
He said: “Any assertion that this results from poor farming practices, profit obsession, or overstocking is misleading and inaccurate.” He went on to explain that jellyfish stings can harm the salmon’s eyes, skin, and gills, potentially leading to health complications and death.
However, environmental campaigners and animal welfare groups have expressed significant concerns about the incident.
John Aitchison, representing the Coastal Communities Network (CCN), which includes 30 member organisations dedicated to safeguarding Scotland’s coastal and marine ecosystems, noted that the prevalence of mass fatalities among farmed salmon is escalating.
“We anticipate further salmon fatalities in Scotland as farms continue to grow in size,” Aitchison warned. The incident has reignited debates about the expansion of Scotland’s salmon farming sector.
“At the end of last year, when mortality rates in Scottish farms reached unprecedented heights, nature broadcaster Chris Packham called for a halt to the industry’s growth.
The mass mortality event has also raised questions about animal welfare standards in the industry. While Mowi’s farms, including those in the Hebrides, hold RSPCA Assured certification for elevated standards of animal welfare, the recent deaths have not jeopardised this certification.
An RSPCA Assured spokesperson stated that outbreaks of disease linked to jellyfish and other waterborne issues are beyond the supplier’s control.
Despite these issues, salmon remains the UK’s second most popular fish after tuna, with sales amounting to £1.3 billion in the year leading up to June. This incident may potentially impact the supply chain for major UK retailers, although the full extent of the consequences remains to be seen.
