Mowi Scotland reports strongest fish health performance in five years.
Mowi Scotland has recorded its best fish health results for the first half of 2025 compared to the same period over the past five years, citing improvements across a range of biological and operational indicators.
The company reported a 20% reduction in mortality by biomass and a 45% reduction by number, alongside improved treatment of gill infections and bacterial diseases. Sea lice levels are also at their lowest since 2017, and fish harvested in the first half of the year have shown strong feed conversion ratios and weight gains.
“All the investment in wellboats, vaccines, post smolt and feeding operations, together with adapting our strategies, is paying off,” said Herve Migaud, Director of Health, Welfare and Biology at Mowi Scotland. “So far this year, we have witnessed the best fish health and welfare for five years.”
Mowi highlighted the role of daily monitoring, enhanced training, and preventive health strategies in achieving these results. Harmful plankton bloom impact has been mitigated through increased vigilance and staff training, while bacterial-related mortalities have fallen by 79% year-on-year. The company attributed this in part to its new vaccine regimes and enhanced biosecurity.
The average monthly mortality for salmon at sea stood at 0.77% in H1 2025, down from 1.14% in 2024. Gill-related mortality also declined, averaging 0.1% per month, compared to 0.28% last year.
At Mowi’s Gorsten farm, a feed conversion ratio of 1.002 was recorded. The company credited both its in-house feed production and remote feed management from its Fort William-based control centre.
Mowi’s post-smolt strategy was also cited as a driver of improved performance, with the first crops harvested between 11 and 14 months at sea. Freshwater operations showed similarly strong performance, including record smolt transfers to sea.
While celebrating the results, Migaud noted that challenges remain. “There are still areas where we would like to see improvements, such as cardiomyopathies and saprolegnia control in freshwater,” he said, pointing to the company’s selective breeding programme as a key long-term strategy.