Pescatarian Diet

What's the environmental impact of being pescatarian?

written byMatt Davies Co-Founder, Mossy Earth

Matt Davies

If you want to change to a more climate friendly diet but you are not yet ready to take the plunge to become fully vegan or vegetarian, becoming a pescatarian might be the right choice to minimise your environmental impact. Alongside the health benefits associated with plant-based diets, seafood will give you those extra omega-3 fatty acids, known for their heart-protective and anti-inflammatory properties. However not all seafood choices are good for the environment and in this guide we will try to break it down for you so you can become the most sustainable pescatarian with a minimal environmental impact.

The carbon footprint of seafood

Compared to other meat products, seafood has lower emissions: first of all, fish don’t produce greenhouse gases and second, no large-scale deforestation for grazing and agriculture is required.

Seafood’s emissions come from transportation in the supply chain, fuel and bait required for fishing, and energy and feed in the case of aquaculture. Therefore, some species have a higher carbon footprint than others. On the top of the list are shrimp, catfish, whitefish, or tilapia, while the species with the lowest environmental impact are shellfish and mollusks and small fish like sardines, mackerel, herring, etc.

A bar chart showing the carbon footprint of various UK diets, in pounds of CO2-eq per day
Source: Scarborough et al. 2014

Transportation and fuel

The first thing to consider as a pescatarian is how far you live from the coastline or fresh waterways - the longer the distance, the more emissions from transportation.

Second, is the choice in seafood - small fish have a lower environmental impact because catching them doesn’t require much fuel. These species swim in dense groups, so an entire swarm of thousands of fish can be pulled up in one trip. The average fuel required per tonne of catch is less than 80 litres. This is not the case for crustaceans like prawns or lobsters, where around 10.000 litres of fuel per tonne of catch is needed because of the heavy net that needs to be dragged through the water and the motoring from one lobster trap to another. A lot of fuel is burned also for migratory species, such as tuna, where large boats need to travel the high seas.

Two fishing trawlers casting their large drag nets out on the high seas
80 litres per tonne of catch compared to 10,000 litres is a huge differnce.

Aquaculture vs. Wild fish catch

There are pros and cons for both aquaculture and wild fish catch, and again it depends on the species. In the case of wild catch, besides the fuel required for the boats, there is the risk of overfishing and the depletion of fish stocks which can affect the entire ocean ecosystem. Sadly almost 90% of global marine fish stocks are fully exploited so a more sustainable management is required in the fishing industry.

Aquaculture is the farming of water organisms including fish, molluscs, crustaceans and aquatic plants. They can be more or less sustainable depending on the type of energy used and the amount and type of feed required. Shrimp, prawns, catfish or tilapia can end up having as much emissions as pork and beef production. Shellfish such as oysters or mussels, on the other hand, are the most climate-friendly. Not only do they not require pellets, as they are filter-feeders, but if grown together with kelp (seaweed), they can help in terms of ocean acidification and provide small carbon sinks.

Offshore oyster beds at low tide
Farmed oysters are one of the most climate-friendly seafood options.

Guides and certifications

As a pescatarian, there are many things to take in consideration when buying seafood. Therefore, we compiled a list of guides, certifications, and apps to help you minimise your environmental impact:

Seafood Watch app - you can search for seafood quickly and easily by common market name and Japanese names in case of sushi. You can find out information about seafood all over the world and get recommendations for the best products, certifications, and even restaurants and stores near you that serve ocean-friendly seafood.

www.seafoodwatch.org - a list of eco-certifications for both farmed and wild-caught seafood

Seafood carbon emission tool - you can explore, calculate and compare the carbon emissions of all farmed and wild-caught seafood species

www.fishforward.eu - Guides created by WWF for different European countries that offer information about the country’s most common seafood products. Recipes and “fish stories” are showcasing WWF-recommended species.

www.mcsuk.org - a guide for sustainable seafood in the UK. Includes over 100 species, which are rated by the from 1 “Best choice” to 5 “fish to avoid”, based on environmental impact, animal welfare, and other sustainability criteria.

A person using a sustainable seafood app. An essential app for anyone adopting a pescatarian diet
An essential app for anyone adopting a pescatarian diet

5 Takeaway Tips

Takeaway tips for a pescatarian to reduce their environmental impact.

1. When choosing a pescatarian diet, it is best if you live close to the coastline or fresh waterways

2. Try to buy fresh, local seafood

3. Look for eco-certifications

4. Inform yourself about the different species and their impact on the environment

5. Download a sustainable seafood app

A grilled fish and colourful fresh vegetables served on a black plate
Enjoy a healthy and sustainable diet!

A sustainable pescatarian diet can have up to a 50% lower carbon footprint than a regular meat eating diet.

Scarborough et al. 2014

Safety Hand

Adopt a pescatarian diet to reduce your footprint

When choosing a pescatarian diet, it is best if you live close to the coastline or fresh waterways
Try to buy fresh, local seafood
Look for eco-certifications
Choose seafood with the lowest footprint: bait fish, oysters or mussels
Inform yourself about the different species and their impact on the environment
Download a sustainable seafood app
Enjoy a healthy and sustainable diet!

Sources & further reading

Peer Reviewed Research Section
  1. Eating seafood can reduce your carbon footprint, but some fish are better than others - OceanaExternal link
  2. The right seafood choices help fight climate change - Yale Climate ConnectionsExternal linkIcon Peer Review
  3. Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK - Research GateExternal linkIcon Peer Review
  4. Pescatarian vs. Vegetarian - U.S. News - HealthExternal link
  5. Pescatarians' Effect On The Environment Vs. Vegans' Shows Anything Helps - BustleExternal link
  6. Food’s Carbon footprint - Green EatzExternal link
  7. 90% of fish stocks are used up – fisheries subsidies must stop emptying the ocean - World Economic ForumExternal linkIcon Peer Review

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