How to Eat Fish Sustainably: Advice from a Marine Scientist

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Sustainable eating is a really interesting and important topic. Fish have so many nutritional benefits, but I find that trying to make sustainable choices about which fish to choose can be a minefield, and advice about this is often vague. So I am delighted with this informative guest blog post by Joakim Nilsson which explains the current situation about sustainable fish consumption, including some practical tips about how to achieve this. 



Joakim is a Marine Scientist from Sweden, he also grew up by the sea and is currently working as a commercial diver with the Swedish navy. Joakim is passionate about raising awareness about how to make more sustainable choices when we are buying fish in shops and restaurants. I hope you enjoy this fantastic post as much as I did! 🐟


There are many good reasons to eat fish, including nutritional benefits, cultural reasons, religious reasons, and of course many people enjoy the taste! But fish consumption can be a sensitive topic because of economic reasons, and the variety of viewpoints associated with it.

This post provides an objective overview about how to eat fish sustainably.


Fishing has been the primary food source for humans for over 10,000 years. The sea was previously thought to be an unlimited food source, so the concept of ‘overfishing’ only emerged in recent human history.

The graph below from the FDA shows how quickly the fishing industry is growing. 70 years ago the total amount of fish caught in the world was only a quarter of what it is today. 

Unfortunately, the dream of having unlimited fish in our seas is over.

It was identified in 2012 that 87% of fish stocks worldwide were either fully exploited or overexploited. 


Graph source: figure one from the FAO ‘The State of World Fisheries and Aquaculture 2012

Different factors contribute to overfishing, such as: using more effective fishing tools and bigger boats; larger demands from an ever increasing population; as well as environmental changes and modifications.

Overfishing can lead to: species becoming extinct, collapsing populations of fish, devastated sea floors and damaged ecosystems.

Examples include: the collapsed salmon population in Canada; and the fact that the fishing boats in countries like Japan, India and China must travel further and further offshore in order to find fish.

Fish have also become smaller in size in recent years; this is related to overfishing and because fishing nets only allow small fish to pass through. Listening to old fishermen’s tales gives us an idea of the numerous shoals of fish and their size, even if these stories may be slightly subjective!

Back in the 60s it was common to catch tuna by the coast of Sweden, but today they are so rare that just a sighting of tuna must be reported to the government.

When speaking about fishery in science we use the phrase ‘shifting baseline’ which means that what we consider to be normal today might not have been normal in the past (i.e. the baseline has changed). Traditionally fish were bigger, more plentiful and easier to catch; but unfortunately this situation has changed.

Although it can be difficult to ignore fishing traditions, it is crucial to consider the wider environmental impact of overfishing.

Figure source: WWF Fish Forward Website (accessed 27/04/18)

Fish Farming:

Today’s leading fish farming countries are Chile, Norway and China.

Fish farming is smart, as it can help to save natural populations of fish.

However, farmed fish live shorter lives, grow more quickly, and behave differently compared to natural populations. This type of farming also poses many ethical and practical questions, such as the widespread use of antibiotics in fish food preparation. This antibiotic use is a precautionary measure in order to prevent diseases that may occur in crowded environments. But these antibiotics can be leaked into the sea which can cause problems, such as the spread of multi-resistant bacteria, eutrophication and much more.

There are of course many ways to farm fish and it is hard to separate all of the environmentally friendly and non-environmentally friendly methods.

Fish to Limit if you are Aiming to Eat Sustainably*:

*Please note the linked videos show some graphic images of fishing practices. Also be aware that these may not be entirely objective.


Tuna: Tuna is a top predator which has an important role in the environment (for more information about the importance of top predators see this video*). In recent years tuna has become endangered all over the planet. However there are several species of tuna which are more sustainable to choose as they are under less threat, such as Albacore tuna. Check out the apps mentioned below for updates about more sustainable choices.   


Shark: These are also top predators and only shark fins are consumed, as rest of the meat is unusable. Fins are usually removed while the shark is still alive, so this is very cruel and wasteful. You can watch this video* for more information.


King prawn/Tiger shrimp/Gambas/Scampi: This is a complicated topic, but tropical giant shrimps and prawns which are farmed in Asia are very bad for the environment (see this video* for more information). Prawn, shrimps and gambas are different names for the same fish (some claim it to be a matter of size). Small shrimp which is locally fished around the Atlantic and north sea is usually fine but it is best to avoid the big shrimp. Scampi such as Norwegian lobster and Dublin Bay prawns are not as bad if fished sustainably with the right fishing tools. If you like shellfish it is best to eat smaller species which are caught close to your country; Pandalus Borealis is one of the species usually caught in the North Sea and the Atlantic.


Eel: We still can’t find where they reproduce but what we do know is that all eels come from somewhere around the Sargasso sea, they reproduce slowly and travel far. It is difficult to understand this species, so we don’t currently know how big the human impact on them is. What we do know is that we are seeing fewer eel in our waters.


Whale: Large animals tend to have a large impact on earth and these giants have been hunted for years. They are mammals like us, they live long lives and have slow reproduction. Smaller species such as Dolphins might be sold as shark fin soup, while bigger species have been hunted for all kinds of reasons i.e. oil, food, sport etc. Whaling is illegal in many countries, but still occurs in many regions. This video* shows the tradition of Whaling in the Faroe islands off Denmark. 


Turtles: These are facing problems worldwide with reduced reproduction levels. There are several ongoing projects to save populations of turtles.

Top Tips for Eating Fish Sustainably:

  1. Try to avoid eating endangered species (as discussed above) 
  2. There are useful posters and apps such as World Wildlife Federation’s Seafood Fish Guide, Seafood Watch and the Marine Conservation Society Fish Guide (in the UK) which provide updated information about fishing practices and more sustainable fish choices
  3. When reading labels look at the location of capture – this also tells you whether it has been farmed or not
  4. Look out for these signs on your fish packaging or ask the chef in a restaurant:

The Marine Stewardship Council is an organisation that fight for sustainable fishing. If your fish is marked with this it’s a small step in the right direction towards sustainable fishing.

The Aquaculture Stewardship Council fight for environmental friendly ways to farm seafood. If a product has the ASC logo on the label it certifies that environmentally and socially responsible methods of aquaculture have been used.


My best advice is to be aware, open your eyes and invest a little time and energy into knowing what food you eat, where it comes from and how it’s fished. Teachers and friends who are environmentally conscious and whom I have met during my years in university eat fish without hesitation. It’s all about choosing the right type of fish to limit damage to the environment and being aware of unsustainable practices.

Species which are not under threat of extinction and are fished in a safe, environmentally friendly manner can be brought to your table without causing too much harm to nature.


Maeve has been consulting on The Food Medic Educational Hub for 12 months now and has been a huge asset to the team. Her ability to translate some very nuanced topics in nutrition into easy-to-follow, informative articles and infographics is really admirable.

Dr Hazel Wallace

Founder of The Food Medic

Maeve is incredibly talented at sharing scientific information in an easy to understand way. The content she shares with us is always really interesting, clear, and of very high quality. She’s one of our favourite writers to work with!

Aisling Moran

Senior UX Writer at Thriva Health

Maeve has written extensively for NHD magazine over the last few years, producing a wealth of dietetic and nutritional articles. Always evidence based and factual, Maeve creates material that is relevant and very readable. She provides high quality work with a professional and friendly approach. Maeve is a beacon of high quality knowledge and work within the nutrition writing community; and someone NHD magazine is proud to work with.

Emma Coates

Editor of Network Health Digest

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