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Did you know that 80% of the seafood we eat in the UK is made up just five different species? We call them the big five; cod, haddock, salmon, tuna and prawns.

Not only is that really boring, but it's a pretty bad idea. It puts a lot of pressure on a handful of wild stocks and creates demand that drives unsustainable fishing and farming practices.

Take a look at what swaps you could make below and visit our Good Fish Guide to see how sustainable the seafood on your plate is.

Cod is one of the UK's favourite fish, often found in fish and chips dinners. It's a cold-water fish that is generally wild-caught rather than farmed. UK stocks are doing very badly as a result of overfishing, but stocks from Iceland are healthy and are currently at sustainable levels. Atlantic cod is available all year round but it's most abundant in autumn and winter.

Best choice

  • Atlantic cod from North East Arctic, Iceland or Norway
  • Pacific cod from Bering Sea
  • MSC-certified cod

What to avoid

  • Atlantic cod from UK seas
  • North Sea cod

A sustainable swap: hake

Thanks to good management and beneficial environmental conditions hake is now a great sustainable choice.

European hake has a very similar texture to cod: meaty and flaky. Swapping is as simple as substituting same weight/quantity in almost all recipes.

GFG Top Swaps - Cod- Spring 2022 - v2 bg


Tuna are a top predator that can grow up to 3m long and weigh as much as a horse! All the tuna we eat is wild-caught from the ocean. There are lots of different species and some are more sustainable than others.

Generally, the best options are skipjack and albacore caught with pole and line or handline. Make sure you check the Good Fish Guide if you're going to eat tuna as some species are red rated 'Fish to Avoid'!

Best choice

  • Sustainably caught skipjack tuna
  • Sustainably caught Pacific albacore tuna
  • Sustainably caught North Atlantic albacore
  • Tuna caught by pole-and-line, handline or troll fishing
  • MSC-certified tuna

What to avoid

  • All bluefin tuna
  • Yellowfin tuna from the Indian Ocean
  • Tuna caught by gillnet or drift net

A sustainable swap: sardines

Sardines from the southwest UK are a great choice thanks to healthy population sizes and a low impact fishing method.

Sardines are classed as an oily fish meaning it’s packed full of omega-3’s and nutrients.

If you don’t fancy whole sardine fresh from the fish counter, then try tinned, they're just as good!

GFG Top Swaps - Tuna - Spring 2022 - v2 bg


Sourced from all over the world, prawns can be sustainable, depending on what species they are, and where and how they were caught or farmed – check the Good Fish Guide.

Generally, prawns with an eco-label like Organic, MSC or ASC are the best choice.

Best choice

  • Wild cold-water prawns smaller than a 20p coin
  • Northern prawns from Northeast Arctic, Canada or Greenland
  • Prawns labelled Organic or ASC-certified
  • Creel-caught Scottish langoustines (also known as Dublin Bay prawns or scampi)

What to avoid

  • Prawns caught using bottom trawl (otter)
  • Uncertified king and tiger prawns farmed in Indonesia, Vietnam and India

A sustainable swap: mussels

Give warm-water king and tiger prawns a rest. Choose UK rope-grown mussels instead, they’re one of the most ocean-friendly choices you can make.

Grown using low-impact methods, harvested by hand and get all the food they need from the sea around them. They cook in no time, and are packed full of protein and nutrients. What’s not to love?

GFG Top Swaps - Prawns - Spring 2022 - v2 bg


Popular for its tasty, pink flesh packed full of omega-3 fatty acids, salmon is a versatile fish that can be wild-caught (oceans, lakes and rivers) or farmed. Both methods have some issues. Atlantic salmon is struggling in the wild and numbers are dangerously low. Some farming methods are very intensive, leading to environmental problems. Farmed salmon also have to be fed large quantities of wild-caught fish, which may not be sustainably sourced. Most of the salmon found in UK supermarkets will be Atlantic salmon farmed mainly in Scotland.

Best choice

  • Pink, red or keta salmon
  • Wild-caught Pacific sockeye salmon
  • Wild-caught Alaskan salmon
  • MSC-certified wild-caught salmon
  • Organic, Freedom Food or ASC-certified farmed salmon

What to avoid

  • Wild-caught Atlantic salmon
  • Uncertified farmed salmon

A sustainable swap: farmed trout

Closely related to salmon, farmed trout is a great alternative. Look for rainbow trout farmed in freshwater ponds in the UK for the best options.

Trout has a very similar texture to salmon, with a slightly stronger flavour (it’s even more delicious in our opinion!). It’s really widely available in supermarkets and easy to swap fillet for fillet in a recipe.

GFG Top Swaps - Salmon - Spring 2022 - v2 bg


Also a chip shop favourite, haddock is generally a wild-caught sustainable option. However some stocks are running low and haddock often swim in the same areas as cod, meaning haddock fisheries may catch both species. You can protect juvenile fish by only buying fish that are larger than 30cm and avoiding buying fresh fish during the main breeding season of March and April.

Best choice

  • Haddock from the North Sea
  • Haddock from Scotland, Iceland or Norway
  • MSC-certified haddock

What to avoid

  • Small fish, less than 30cm

A sustainable swap: plaice

Why not try plaice from the North Sea, where stocks are booming? Plaice is a flat fish with a light, flaky texture and a mild flavour. It's delicious pan fried with a simple herb butter.

GFG Top Swaps - Haddock - Spring 2022 - v2 bg

We should all try to diversify the seafood in our diets. By mixing up your meals, you’ll help remove some of the strain placed on a handful of farms and fisheries, you'll be supporting more UK suppliers and, who knows, you might discover a new favourite fish.

Health recommendations

The NHS recommends eating two portions of fish per week, but there are guidelines on the amount of certain fish that babies, children and pregnant or breastfeeding women should be consuming. See for more info.

The seafood advice on this page is correct as of April 2022.

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