Seafood more nutritious, produces fewer greenhouse gases than beef or pork, study finds
Researchers assessed dozens of seafood species along with carbon emissions from harvesting
There is more evidence that seafood is a healthier and more environmentally friendly option than beef, pork and chicken, according to a study published Thursday in the journal Communications Earth and Environment.
The authors assessed the nutritional content in dozens of globally important seafood species and the carbon emissions produced to harvest them and compared the results to the big three land-based proteins.
"The really significant result is in some ways something that many of us already had an understanding of — that many seafood systems and, frankly, the majority of seafood available — whether it's from capture fisheries or aquaculture — are very nutritious relative to other major sources of animal protein," said co-author Peter Tyedmers, a professor at Dalhousie University School for Resources and Environmental Studies.
The study found farmed oysters and mussels, wild salmon (pink and sockeye), herring, anchovies and mackerel had the highest nutritional value with the lowest carbon footprint among seafood species.
Some crustaceans like shrimp and lobster and cephalopods like squid or octopus had the highest average emissions, while wild-caught white fish had lowest nutritional scores, the paper said. Fuel use accounted for the greatest portion of greenhouse gas (GHG) emissions in wild-capture fisheries.
"There is a fair bit of fuel that gets burned for every kilo of lobster, tonne of lobster that gets landed at the end of the day," said Tyedmers.
How species were rated
The study developed a "nutrient density" score for 41 seafood species by measuring 21 beneficial nutrients like vitamins, fatty acids and protein in the edible portion of the species. It also measured less desirable contents like saturated fats and sodium.
For 34 of those species, the authors were able to quantify carbon emissions per kilogram.
The global average performance of all seafood assessed, weighted by species production volume, has a higher nutrient density than beef, pork and chicken and lower GHG emissions than beef and pork, the study found.
Half the seafood species had both higher nutrient density and lower greenhouse gas emissions than beef, pork and chicken.
Pork measured just below the average of seafood in both nutrient density and emissions.
Chicken has a much lower nutrient density, comparable to the lowest scored seafood groups.
Time to 'displace' the hamburger patty
Beef scores just under the average seafood nutrient density but results in higher GHG emissions than any other food analyzed.
Nutrient density of seafood is lower than land-based animal products for only a few species, such as some whitefish and Japanese carpet shell.
Tyedmers says the scoring results among seafood species need to be put in perspective.
For instance, iodine is a nutrient that is lacking in many places around the world. Lobster, Atlantic cod and haddock, are good sources of the micronutrient despite not scoring well in nutrient density.
The paper also shows that a kilo of red meat produces five times the carbon compared to lobster and ten times the emissions to harvest haddock.
Urge Canadian industry to open up
"Every opportunity there is for seafood to displace, any seafood to displace, a hamburger patty is an opportunity to effect positive climate action," says Tyedmers.
The study was an international effort with researchers in Sweden that examined data gathered from all over the world.
Tyedmers says the results should encourage the Canadian seafood industry to become more open about its operations, including fuel use. He says companies have become increasingly secretive over the last two decades he has been involved in these studies.
"Now it is nearly impossible to get a fishing company, vessel owner, fleet manager to share data," he said. "This is not a threat in seafood. This is a massive opportunity."
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