In troubled waters

A mass die-off of over one million salmon at a Scottish fish farm last year had many questioning the health of the industry. James Fair asks what the future holds for both fish farmers and consumers

- James Fair

When news leaked that two salmon farms on the Isle of Harris in the Outer Hebrides had lost more than one million fish in mass die-offs over the course of a year and a half because of rising sea temperatures, for critics it was yet another example of the industry's poor welfare and environmental record.

Salmon farming has been under the intense glare of media publicity for decades. The charge sheet includes allowing sea lice and other diseases to proliferate among farmed fish and spread to their wild cousins; the overuse of antibiotics and other chemicals that impact Scotland's delicate marine ecology; and even the shooting of seals that are accused of pilfering the salmon as tasty treats. Some marine conservationists say that, over the years, salmon farming has improved. Yet rising sea temperatures, which produce blooms of micro-jellyfish and plankton that sting and block gills and bring about the onset of amoebic gill disease, are completely outside of any company's control. As climate change continues to ramp up, the mass mortalities are a dark omen for the industry's future.

These large-scale die-offs appear to be becoming more frequent.In November 2022, fishfarmingexpert.​com reported that 2.8 million individual salmon died in September of that year, amounting to nearly 5% of all the fish farmed in Scotland and the worst month for deaths since records began in 2018. Another report found that 10 Scottish salmon farms had suffered 50% mortality rates in 2023, with four of them alone losing nearly two million fish in total. While salmon farming has weathered many storms, could climate change be the wolf that blows the house down?

LEARNING FROM THE PAST?