Why is Information on Fish So Hard to Get?

One thing I have learned from researching fish carbon emissions is that information on fish is confusing. Fish carbon emissions are mostly calculated by the amount of diesel fuel a fishing vessel burns, this mostly is from powering the ship but also includes processing the fish as well as refrigerating or freezing the fish. [1] Different fish also have different emissions. For example, fish that swim close together in schools and stay regularly close to shore requires less fuel. [2] The Seafood Watch program helped create the Seafood Carbon Emissions Tool using this method.

However, these are not the only carbon emissions that can be associated with fishing as the type of commercial fishing method used can also be important. One method called bottom trawling, where a net is dragged along the seafloor, [3] has recently been gaining a lot of scrutiny as a paper published in 2021, [4] suggests it may be releasing on average one gigaton of carbon dioxide. This is almost as much as the 1.05 gigatons the aviation industry releases yearly. [5] This is because the ocean is the world’s largest carbon sink, with much of the carbon being trapped into the ocean’s sediments. When that sediment is disturbed it can release carbon back into the ocean, which can weaken the ocean’s carbon sequestration abilities or re-release the carbon back into the atmosphere. Even more concerning, a 2018 study mentioned how bottom trawling catches around 19 million tons of fish, which is almost one quarter of all wild caught marine life [6].

What makes it even harder to know a fish’s carbon impact is the lack of transparency in the fishing industry. It is already difficult to tell if a fish you are buying is caught or farmed, since it is often not clearly labeled, but it is near impossible to tell which fish is caught by what method. What makes the matter even more complicated is the issue of Seafood Fraud. Oceana states that seafood fraud “is the practice of misleading consumers about their seafood in order to increase profits.” [7] This includes mislabeling one species for another (especially claiming a cheaper fish is a more expensive one). Oceana released a report in 2016 that found out of 25,000 samples, around 20% were mislabeled. [8] Seafood fraud undermines honest fishery business, threatens marine biodiversity as well as posing health consequences. The global fishing industry is highly unregulated and unenforced, which allows for this lack of transparency and why we have so little data on the fish we consume. This makes consuming seafood especially challenging for those who are trying to eat sustainably.

So how can we purchase seafood that is sustainably farmed? It is best to know where your fish is coming from, which can often be achieved by buying fish from local fish businesses. However, this is not always possible or feasible. If you are in the UK, a blue MSC label indicates that the seafood follows the Marine Stewardship Council guide for sustainable seafood, whether it is farmed or caught. [10] They only give certifications to fisheries that acquire seafood from healthy fishing stocks, are managed so fish will last for the long term, practices that minimize impacts on other species. In the US, Seafood Watch provides consumer guides on what seafood is best to get (and from where) based on region.

[1] Hanlon, P. (2017). Climate-Friendly Seafood - Is There Such a Thing?. Food Print. https://foodprint.org/blog/climate-friendly-seafood-is-there-such-a-thing/

[2] http://seafoodco2.dal.ca/(overlay:menu/5bcb48abaaea53205a2de526) 

[3] Sustainable Fisheries. (2017). Commercial Fishing Methods. https://sustainablefisheries-uw.org/seafood-101/commercial-fishing-methods/

[4] Parker, R.W.R., Blanchard, J.L., Gardner, C. et al. (2018). Fuel use and greenhouse gas emissions of world fisheries. Nature Clim Change 8, 333–337 . https://www.nature.com/articles/s41558-018-0117-x

[5] Graham, D. (2021). Fish ‘not as carbon friendly’ as previously thought. BBC News.  https://www.bbc.com/news/science-environment-57202758#:~:text=Previous%20research%20indicated%20that%20seafood,or%20the%20care%20of%20livestock.

[6] Amoroso, R., Pitcher, C., Rijnsdorop, A. et al. (2018). Bottom trawl fishing footprints on the world’s continental shelves. PNAS. Vol. 115, No. 43. https://www.pnas.org/doi/10.1073/pnas.1802379115

[7] Oceana. (2016). What is Seafood Fraud. Oceana. https://oceana.org/what-seafood-fraud/#:~:text=Seafood%20fraud%20is%20the%20practice,conservation%20efforts%20and%20human%20health.

[8] Oceana. (2016). Deceptive Dishes: Seafood Swaps Found Worldwide. Oceana. https://usa.oceana.org/reports/deceptive-dishes-seafood-swaps-found-worldwide/

[9] Mustain, P. (2016). There’s Some Fishy Business in the Global Fish Business. Scientific America. https://blogs.scientificamerican.com/food-matters/there-s-some-fishy-business-in-the-global-fish-business/

[10] Marine Stewardship Council. What does the blue MSC label mean?. Marine Stewardship Council. https://www.msc.org/what-we-are-doing/our-approach/what-does-the-blue-msc-label-mean

[11] https://www.seafoodwatch.org/recommendations/download-consumer-guides