15 April 2020

How sustainable is seafood?

AT SPECIFIC™ we use fish as a main ingredient - both for its health benefits and to help us to deliver our sustainability commitments.

Global agriculture feeds over 7 billion people, but with major environmental impacts 

  • Half of the world’s habitable land is used for agriculture
  • Food accounts for over a quarter of global greenhouse gas emissions1
  • 70% of global freshwater withdrawals are used for agriculture2
  • 78% of global ocean and freshwater eutrophication (the pollution of waterways with nutrient-rich pollutants) is caused by agriculture1

Food production impacts the environment through

  • Methane from enteric fermentation
  • Nitrous oxide from feed production
  • Emissions from manure management
  • Changes in soil organic carbon and the consequential emissions of CO2
  • Fossil fuel and electricity usage


Different sources of protein have different environmental impact with the carbon footprint of the worst being up to 100 times larger than the best.

  • Ruminant meat has the highest impact 
  • Pork has mid-range impacts 
  • Vegetal products, certain seafood, and poultry all have smaller carbon impact


There are huge differences in the sustainability of fish with the most sustainable forms of seafood having an environmental impact equivalent to the lowest emitting foods and the worst seafood having emissions the same as the highest emitting foods.

  • North East Atlantic Mackerel5; Baltic herring6 and Spanish mussles7 all produce only 1 kg CO2-eq per edible kg of food – similar to that from pulses. 
  • At the other end of the scale trawled Norwegian lobster8 produce 86 kg CO2-eq per kg of food. 
  • There are big differences depending on the type of fishing with North East-Atlantic Mackerel caught by the Basque ring netting fleet produce only 1 kg CO2-eq per kg of food but that caught by the Galician bottom trawl fleet produces 6 kg CO2-eq5.


The main factor in the environmental impact is fishing method 

90% of emissions from seafood come from marine fuel and the type of fishing has a huge impact on fuel use.

Bottom trawling, tows a net along the sea floor and is used to catch bottom-living fish such as cod, squid, shrimp, and rockfish. This method uses more fuel and causes seabed damage.


Midwater trawling pulls a net higher in the water than the bottom of the ocean and is used to catch pelagic fish such as anchovies, and mackerel. This style of fishing uses much less fuel.

Ring netting (also known as purse seine netting) uses a net to encircle a shoal of fish forming a deep curtain of net, which is suspended vertically through the water. The net is then drawn in to land the fish. Fuel use is low, as the net is not towed through the water, and by catch minimised as if the wrong species is in the net then whole catch is released unharmed before it is landed.



  • Fewer methane emissions from fish – a major environmental impact of livestock farming. 
  • Feed conversion ratios (the amount of food eaten by an animal relative to the amount of food produced by the animal) are better for fish. Fish are cold blooded so don’t use energy maintaining body temperature and are supported in water, so the fish use less energy moving and staying upright.
  • Fishing does not use valuable arable land


  • Our salmon is farmed 
  • Our caught fish is mostly midwater trawled Herring and Blue whiting and ring net caught Atlantic Sardine 
  • All of our fish in our dry diets come from sources certified as sustainable

1 Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science 360 (6392), 987-992. 
2 FAO. (2011). The state of the world’s land and water resources for food and agriculture (SOLAW) – Managing systems at risk. Food and Agriculture Organization of the United Nations, Rome and Earthscan, London. 
3 Nijdam, D., Rood, G., Westhoek, H. (2012). The price of protein: Review of land use and carbon footprints from life cycle assessments of animal food products and their substitutes. Food Policy. 37. 760–770. 10.1016/j.foodpol.2012.08.002. 
4 Seafood emissions tool
5 Ramos, S., Vázquez-Rowe, I., Artetxe, I., Moreira, M.T., Feijoo, G., Zufía, J. (2011). Environmental assessment of the Atlantic mackerel (Scomber scombrus) season in the Basque Country: increasing the timeline delimitation in fishery LCA studies. International Journal of Life Cycle Assessment 16, 599–610. 
6 Silvenius, F., Grönroos, J. (2003). Fish Farming and the Environment: Results of Inventory Analysis. Finnish Environment Institute, Helsinki 
7 Iribarren, D., Vázquez-Rowe, I., Hospido, A., Moreira, M.T., Feijoo, G. (2010) b. Estimation of the carbon footprint of the Galician fishing activity (NW Spain). Science of the Total Environment 408, 5284–5294
8 Ziegler, F., Valentinsson, D. (2008). Environmental life cycle assessment of Norway lobster (Nephrops norvegicus) caught along the Swedish west coast by creels and conventional trawls – LCA methodology with case study. International Journal of Life Cycle Assessment 13, 487–497