At a village hall near Loch Linnhe, a sliver of water sandwiched between the Hebrides and Glasgow, Stewart Hawthorn laid out his plan to build the biggest salmon farm in the UK near this aging rural community. Once completed, the managing director of Long Loch Salmon said, it would create at least 16 jobs. It would feature eight enclosures holding up to 8,000 tons of fish, with a density double the industry standard. And most importantly, he claimed, it would help alleviate one of the biggest problems plaguing the business — excessive death rates.

Salmon is a hot commodity: its aquaculture is the fastest-growing food production system in the world. Promoted as a healthy alternative to red meat and chicken — and a way to to close the so-called “protein gap” for a growing global population — Atlantic salmon production has expanded more than six-fold since 1995. The fish is now the UK’s dominant food export, with much of the farming taking place in Scotland.