[animals] ‘Monstrous’ sea lice and jellyfish invasions blighting Scottish salmon farms

Mr.Jhorjan · September 20, 2023

Lochs in the Highlands of Scotland are among the most spectacular and pristine wildlife areas in Britain, attracting tourists from around the world. They are also a production line for what have become supermarket staples: smoked and fresh salmon.

The salmon industry says fish health and welfare are at the heart of successful Scottish salmon farming, but a new investigation by Viva!, the vegan campaigning charity, highlights the parasites and jellyfish blighting intensive fish production.

Campaigners deployed cameras with underwater drones at salmon farms operated by some of Scotland’s biggest producers. They recorded what they call “monstrous invasions” of sea lice and swarms of jellyfish.

Lex Rigby, head of investigations at Viva!, said: “The intensification of fish farming as a ‘solution’ to overfishing has created a breeding ground for disease in which salmon suffer appallingly.”

The sea lice – Lepeophtheirus salmonis – feed on the salmons’ skin and are potentially lethal to the fish. They are typically treated with licensed medicines or physical methods including bathing in freshwater.

Live! filmed at salmon farms in Loch Torridon, Loch Carron and Loch Kishorn in the north-west Highlands of Scotland. The footage shows many salmon infested with parasitic sea lice. The farms are operated by leading food producers supplying UK supermarkets and overseas markets, with salmon now one of Britain's biggest food exports.

Footage taken at a seawater farm on Loch Torridon operated by Mowi, the world's largest supplier of farm-raised salmon, shows several salmon infested with sea lice. The farm's own official reported counts in 2023 of weekly average female adult sea lice per fish have been between 0.03 and 5.4. Treatments for infestations are started when there is an average of between 0.5 and one adult female lice per fish.

Filming at the Bakkafrost salmon farm at West Strome, Loch Carron, also showed fish lice infestations. The farm's own official reported counts in 2023 of weekly average female adult sea lice per fish have been between zero and 2.14. Filming at three farms operated by Scottish Sea Farms at Loch Kishorn showed sea lice and swarms of jellyfish.