Scientists reveal that the idea that shellfish farms capture atmospheric carbon dioxide (CO2) is wrong. In reality, shellfish emit CO2 while making their shells. Shellfish farming therefore does not contribute to the fight against global warming.
The essentials of the day: our exclusive selection
Every day, our editorial team reserves the best regional news for you. A selection just for you, to stay in touch with your regions.
France Télévisions uses your email address to send you the newsletter “The essentials of the day: our exclusive selection”. You can unsubscribe at any time via the link at the bottom of this newsletter. Our privacy policy
In an article published in Reviews in Aquaculture, scientists reveal that shellfish release CO2 contrary to popular belief.
“Fake news spreads much faster than the truth. This is what we wanted to demystify“, declared to AFP Fabrice Pernet, researcher in the ecology of marine organisms at Ifremer, main author of the article.
Mr. Pernet became interested in the issue during his interactions with the shellfish industry. “I had a lot of questions about granting carbon credits to shellfish farming“for its supposed role in CO2 sequestration,”and I didn’t understand why people were asking me the question“, he explains. “I always learned at school that the only living CO2 sinks were plants.“
But the idea has spread that shellfish sequester CO2, a bit like the wood of trees, because the shell of oysters, mussels and other clams is made of carbon.
A Chinese study, published in 2011 in a marine ecology journal, and cited more than 200 times since, propagated this idea. Since then, 28 scientific articles, out of the 51 examined by Mr. Pernet and his co-authors, have taken up this reasoning.
ALSO READ : “This year, it’s a real disaster”, green algae is suffocating oysters in the bay of Morlaix
In April 2022, the Aquaculture Advisory Council even recommended that the European Commission study a mechanism for paying carbon credits for CO2 sequestration by shells. “It’sis totally false, it is absolutely not CO2 that is used” to make the shells, but bicarbonate coming from the erosion of rocks, underlines the researcher.
Far from storing CO2, calcification, at the origin of the manufacture of the shell, releases it into the water and thus reduces the capacity of the ocean to absorb that which is present in the atmosphere.
The study nevertheless underlines that shellfish farming provides numerous ecological services (clarification of sea water, regulation of nitrogen and phosphorus, etc.) and remains “the least carbon-intensive way to produce animal proteins“, says Mr. Pernet. But “the idea is to avoid wasting public money on subjects that are not“, he adds.
ALSO READ : Morlaix: oyster farmers denounce the deterioration of water quality and point to faulty sanitation systems
To reduce CO2 emissions from shellfish farming, the authors recommend putting waste from consumed shells back into the sea, where they will dissolve and trap CO2. Or grow algae next to shellfish.
(With AFP)
Related News :