The Big Five Fish Species

The big five refers to the five species of sea creatures which are the most commonly eaten in the UK. These are:

  • Cod
  • Haddock
  • Tuna
  • Salmon
  • Prawns

These five species make up between 60 – 75% of all seafood eaten in the UK (different sources give different figures for the exact percentage the big five make up). All other seafood (shellfish, fish species, crabs, lobsters and other crustaceans) fall into the remaining 25 – 40%.

Why are the Big Five Species so Popular?

The popularity of the big five species is often put down to the deeply unadventurous culinary habits of the British public. Cod and haddock are both whitefish which produce delicate, flaky white flesh when cooked which has a fairly sweet, mild flavour. The vast majority of cod and haddock bought by UK consumers comes processed into fish fillets covered in breadcrumbs or batter, or other produces such as fish cakes, fish fingers or other processed fish products.

The Big Five
The big five species. From left to right: cod, salmon, haddock, tuna and prawns.

Only a relatively small amount comes as full, unfilleted fish from a wet fish counter meant for preparation at home. Tuna is massively popular but mostly comes in canned, and prawns are usually sold fresh or frozen but have been peeled, shelled and prepared. Salmon is usually sold in chilled or fresh fillets. Clearly, the vast majority British public prefer fish which is already pre-prepared. This is due to the fact that fish is this form is quicker and less hassle to cook and does not create much mess. Most people also lack (or are unwilling to learn) the skills to gut, fillet and prepare a full fish for the table.

The Impact of Having a ‘Big Five’

The fact that five species dominate the UK market means that there is massive pressure on these species. Cod and haddock stocks around the UK, and the rest of the world, have been reduced due to the intensive commercial fishing of these species and numbers are down on previous generations, although North Sea cod have shown a slight upturn in numbers in recent years. Similarly tuna numbers have been decimated due to the huge worldwide demand – Southern bluefin tuna is classes as Critically Endangered by the IUCN (International Union for the Conservation of Nature) which means it is at an extremely high risk of extinction in the near future. Atlantic bluefin is classed as Endangered and several other species have stock levels which are classed as Near Threatened or Vulnerable. There are also fears that prawns and salmon in British waters are being overfished, and attempts to find an answer via fish farming and aquaculture have ran into their own problems.

The dominance of these five species leads to problems over and beyond fishing unsustainably for these species. It means that other species, such as coalfish, whiting and dab, which are perfectly edible are not as highly valued by consumers and therefore much more difficult to sell. However, in a mixed fishery (which all of the seas around the UK are) it is inevitable that these species will be caught along with the cod and haddock which are being targeted. Usually these low-value species can often be thrown back into the sea dead as unwanted bycatch, or processed into fish products which are exported abroad.

Reducing the Dominance of the Big Five

Spreading fishing pressure across a wider number of species would – in theory – have several benefits. Firstly, eating more species outside of the big five would give over-exploited species the chance to recover and allow stock levels to begin to build back up again. Furthermore, it would mean that species which have a low commercial value (such as dab) will begin to become more valuable and are more likely to be retained by commercial vessels rather than thrown back into the sea as bycatch. There have been active attempts to get people to eat a wider variety of fish: Sainsbury’s have ran the ‘Switch the Fish’ campaign and a major part of Hugh Fearnley-Whittingstall’s Fish Fight campaign has been to get people to eat different species of fish, and Jamie Oliver has backed a similar campaign. Conservation groups such as the Marine Conservation Society (MCS) have also led their own similar campaigns. In 2018 the MCS called for UK consumers to eat species such as hake, dab and the deep-water flatfish megrim in order to take the pressure off traditional species such as cod and haddock.

Alternative Species
Octopus, tilapia and gurnard are all becoming more popular around the UK.

However, some caution is needed. There is nothing sustainable about eating species such as Dover sole if it has been caught by destructive methods such as beam trawling – a form of commercial fishing which wreaks havoc on the seabed and destroys the marine environment. Furthermore, the move away from UK caught cod and haddock may see people switching to fish species which are just as endangered such as shark species, rays or Atlantic wolffish. Even worse is the belief that publicising all these new species simply increases demand for them, but there is no corresponding reduction in the amount of the big five consumed. An article in The Guardian in August 2011 stated that Waitrose Supermarket said that sales of bass, whiting, brill and pollock had increased by three tons a week, but sales of cod and other popular fish had remained “steady.” Similarly, Asda said that mackerel sales were up by 69%, and whole trout up 72%, but cod and haddock sales had also increased. The British think-tank the New Economics Foundation described the promoting of other species as an alternative to the big five as a “risky gamble which could lead to more demand for fish” and stated that “there is no evidence that encouraging people to be more adventurous with new species will ease the pressure on fish stocks.”

So What is the Answer?

UK tastes do appear to be changing and a number of different species appear to be increasing in popularity. If – and only if – these new species are caught in sustainable ways and replace consumption of cod, haddock and other big five species then the impact on UK and indeed world fish stocks could be positive. As the list below shows, species which were once unheard of in UK supermarkets are now selling in greater numbers. Only time will tell if the likes of Hugh Fearnley-Whittingstall are right and the consumption of the big five species will decline as a result.

Species which are Increasing in popularity

The following fish species have increased in popularity at the following supermarkets:


John Dory up 775%
Red Gurnard up 475%
Dab up 195%
Pouting up 16.5%
Source: The Grocer


Seabass up 57%
Pollock up 15%
Trout up 29%
Tilapia up 117%
Source: The Guardian


Bass up 100%
Basa Fish up 30%
Sea Bream up 40%
Source: The Mirror

Pouting up 273%
Dab up 120%
Gurnard up 100%
Sea Bream up 50%
Source: The Guardian

Other species which are becoming increasingly popular across all UK supermarkets:

Fresh Cuttlefish, Octopus and Squid
Dover Sole
Turbot and Brill
Grey Mullet
Source: Daily Mail