Atlantic salmon - Dawn Purchase

Salmon is one of the most popular fish used for food. Here we explore what to think about and what to look out for to make sure you're buying sustainable salmon when you shop.

Where does salmon come from?

Popular for its tasty, pink flesh packed full of omega-3 fatty acids, salmon is a versatile fish that can be wild-caught (in oceans, lakes and rivers) or farmed. Most of the salmon found in UK supermarkets is Atlantic salmon, farmed mainly in Scotland, but it can also be from Norway, Chile and the Faroe Islands.

You won’t see wild Atlantic salmon in the supermarkets as numbers are dangerously low. If you spot it in your local fishmongers or when at a restaurant, you should avoid it.

Wild caught Pacific salmon (keta, red, pink) can often be found in tins, or occasionally in the fresh aisle as fillets.

Farmed salmon is the single most popular fish consumed in the UK. It’s also the biggest fish farming sector in the UK, producing around 205,000 tonnes in 2021, and is both Scotland and the UK’s top food export. In the UK, salmon farming takes place in coastal waters off the west coast of Scotland and around Shetland, Orkney and the Western Isles, all known for their stunning landscape and cool waters.

How is salmon farmed?

Young salmon are raised from eggs in indoor hatcheries and then grown as juveniles in either land-based tanks or in freshwater lochs until they are ready to go to sea. Once at sea, they grow in open net pens for around 18 months until they reach adult size of around 4-6kg. These open net pens allow for the constant flow of seawater in the pens.

Alternatively, in Denmark, a small number of Atlantic salmon are farmed in recirculating aquaculture systems (RAS). These systems are fully enclosed on land and have little or no impact on the surrounding environment.

Salmon farm

Credit: Dawn Purchase

What do eco-labels tell us about salmon?

Eco-labels can often be seen on seafood packets, and occasionally appear on restaurant menus. They’re an easy way to check if seafood is responsibly farmed or sustainably caught. An eco-label shows that a particular seafood product has been independently certified to a set of criteria by a third-party auditor.

Look on the Good Fish Guide to find out more about certified Atlantic and Pacific salmon.

How sustainable is farmed salmon?

Salmon farming is a complex process that requires lots of considerations, especially as it happens in a dynamic, diverse and ever-changing environment.  Each farm is different. Some have better practices than others, and some are sited in locations that are more suited to fish farming.

However, challenges remain for most farms in some form. Open net pens allow for waste products such as faeces, uneaten feed, and medicinal treatments to enter the sea and affect the seabed. Fish may escape from open net pens, which can cause problems if they breed with wild salmon. Diseases can spread between farmed fish and wild fish. Sea lice, which are small marine parasites, are also passed between farmed salmon in pens and wild salmon. They can cause health problems for fish if they attach in large numbers.

Farmed salmon require feed which includes fishmeal and fish oil, which comes mainly from wild caught fish. Terrestrial ingredients such as soy are also used. These ingredients are not always sustainably sourced.

Salmon at farmers market Ekaterina Pokrovsky

Credit: Ekaterina Pokrovsky via Shutterstock

Most salmon is rated as OK – needs improvement on the Good Fish Guide, indicating that it needs improvement in one or more of these areas.

What improvements do we want to see in Scotland?

We still have concerns about Scottish salmon farming. Until these are addressed, we believe the industry should not be considering any further expansion in its current form.

The more salmon farms there are in one area, the more impacts could accumulate and affect the environment. Currently, there is no way of measuring what these cumulative impacts are. This is worrying, because without understanding the full impact of multiple farms in one area, we cannot work out what the overall health of the environment and its habitats and species will be.

We’re also concerned about the lack of knowledge of salmon farming impacts on sensitive habitats and species and near Marine Protected Areas (MPAs). There are 103 known active farming sites within MPAs.

We want the Scottish Government to provide support and incentives for the promotion of new and innovative developments that show real environmental benefits. We also need them to ensure aquaculture is spatially managed so that the cumulative impacts of salmon farming and other activities, such as wind farms and aggregate dredging, are fully accounted for.

You can read about what we think about the Scottish Government's Vision for Sustainable Aquaculture (2023) here.

Is wild caught salmon a better alternative?

Simply put, neither wild caught nor farmed salmon is better than the other. Both have species on the Best Choice and Fish to Avoid lists, with many options in between.

All wild caught Pacific salmon are currently a Best Choice option on the Good Fish Guide, as populations are doing well. However, it’s got to be transported to the UK from Alaska. There are five species of Pacific salmon, with three being readily available to buy in the UK. These are keta (also known as chum), red (also known as sockeye) and pink (also known as humpback).

You can find out more about Pacific salmon here:

Wild caught Atlantic salmon is a Fish to Avoid. It’s struggling in the wild and you should always choose a more sustainable alternative. You can find out more about it on our Good Fish Guide.