Plenty of fish in the sea? Farmed salmon industry challenged to overhaul feed practices to protect wild fish

New research has shown we could eat a healthy diet and leave more wild fish in the sea if we ate a wider range of wild fish, and less farmed salmon. With NHS dietary guidelines encouraging UK citizens to eat at least two portions of fish a week, farmed salmon is often perceived as both a healthy choice, due to its high omega 3 content, and an option that relieves pressure on wild fish populations. But new modelling has shown that to access the same level of omega 3 and other micronutrients currently produced by the Scottish salmon farming industry, we should eat a lot less salmon, and more of a diverse range of wild fish, including sardines, anchovies and sprat . By doing so we could leave 59% of fish currently caught to feed farmed salmon in the sea, helping to protect wild fish populations and ocean ecosystems.

Farmed salmon is popular: it is the most purchased seafood in UK supermarkets , and Scottish farmed salmon is one of the UK’s top food exports by value . But farmed salmon’s omega 3 content is largely delivered by the inclusion of wild fish in its feed in the form of fish oil: previously, Feedback calculated that the Scottish salmon industry uses around 460,000 tonnes of wild fish a year for this purpose, roughly equivalent to the quantity of seafood purchased by UK adults every year – and roughly 90% of these fish could be eaten by people.

New modelling has shown that if we made more the wild fish currently used to feed farmed salmon, including herring, anchovies and sardines, alongside a smaller quantity of farmed salmon, we could leave 273,000 tonnes of wild fish currently used by the Scottish salmon industry in the sea. If we added farmed mussels to our diet, which do not need feed and which contain high levels of micronutrients, we could leave 77% of wild fish caught for salmon feed in the sea, or around 354,000 tonnes.

Key takeaways

  • Every year the Scottish farmed salmon industry uses around 460,000 tonnes of wild fish to make fish oil to feed to farmed salmon, resulting in around 179,000 tonnes of farmed salmon.
  • Feedback have calculated that if we ate some of these wild fish directly, and cut our consumption of salmon significantly, we could access the same level of omega 3 as is currently delivered by Scottish salmon farming, while leaving 59% of wild fish – around 273k tonnes – currently caught for feed in the sea.
  • Salmon farming in Scotland suffers from high mortality rates – in 2019, the farmed salmon that died before being harvested led to a waste of around 25,000 tonnes of wild fish in the form of feed, enough to feed 2 million people their weekly portion of oily fish for a year.
  • If we added some farmed mussels to our diets, we could leave up to 77% of wild fish – around 354k tonnes - currently caught for salmon feed in the sea.
"While the Scottish farmed salmon industry may cultivate a reputation for clean and green nutrition, our evidence shows that producing farmed salmon is actually creating a wasteful and unnecessary burden on our oceans: this industry is more about corporate profit than it is about healthy and sustainable food."

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Plenty of fish in the sea? Read our reports examining the role of Scottish farmed salmon in future food security.

Do you know what your farmed salmon eats? The current quantity of wild fish fed to farmed Scottish salmon, 460,000 tonnes is roughly equivalent to the amount of seafood purchased by the entire UK population

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