Study shows rapid seabed recovery following the closure of Mowi’s Isle of Ewe fish farm on Scotland’s northwest coast.
A three-year post-closure environmental study around Mowi’s former Isle of Ewe fish farm on Scotland’s northwest coast has revealed encouraging seabed recovery data. The study, conducted by Mowi in collaboration with Benthic Solutions and Applied Genomics, and supported by Salmon Scotland, assessed environmental recovery after the fish farm’s closure in late 2020.
“Isle of Ewe had been in operation since 2005,” said Connie Fairburn, Senior Environmental Analyst at Mowi Scotland. “Prior to its closure in late 2020, the site had a lot of diverse features present within the area which warranted the designation of the Wester Ross Marine Protected Area, which goes to show that Mowi sites can coexist alongside protected areas quite successfully.”
Ian Wilson, Founder of Benthic Solutions, elaborated on the study’s methodology: “We looked at how the seabed recovered in multiple different ways, not just seabed sampling with benthos and macro invertebrate analysis, but we also integrated an environmental DNA analysis which covers a much bigger profile of the biodiversity. We also did habitat mapping and photography.”
The study followed sampling from the ‘allowable mixing zone’—an area limited to 0.3% of Loch Ewe’s surface area, extending 100 meters around the fish pens. According to Fairburn, “the Isle of Ewe fish farm complied with all seabed environmental standards prior to its closure.”
Rapid recovery
In 2020, 67% of sampling locations met standards for ‘Good Ecological’ status, which rose to 80% in 2021, 93% in 2022, and reached 100% by 2023. Wilson noted, “The results we received from the data were initially very, very positive… We found that the distance to where the biodiversity shifted significantly halved within those six months.”
Iain Berrill from Salmon Scotland remarked, “The project has been really important because it has shown us… that the seabed will recover… very, very rapidly.” He emphasized that this “reiterates our position on our understanding that our impacts are only temporary and they’re not long-lasting.”
Fairburn added, “There are many misconceptions about the environmental impact of the aquaculture industry. However, this project provides solid evidence that seabeds can recover upon cessation of fish farming operations.”
