Calling all seafood lovers: To adopt a low-emission, good-for-your-health diet, consider upping your intake of oysters, anchovies, and salmon…but maybe avoid shrimp.
These are the suggestions of a new study that compared the nutritional impact and emissions of different shellfish, focusing on a number of species, including bivalves and small pelagic forage fish, that would be a nutritional match for meat, while at the same time they would have impressively low emissions. .
Countries that consume diets rich in beef, chicken and pork will require a shift to more environmentally sensitive foods to stay in line with climate goals. But when it comes to dietary alternatives, fish has often been forgotten amid increasingly sophisticated plant-based protein substitutes like pea protein burgers and soy chicken cutlets.
where the consumers are urged to replace red meat with fish, seafood is often treated as a unit, disregarding the vast differences in nutritional value and emissions impact between different types, researchers from the new nature communications Earth and Environment study say For example, emission output can be seriously influenced by how fish are caught or, if farmed, what food they receive.
The new seeks to fill this information gap and, in doing so, help encourage the most effective use of fish to move diets in a more sustainable direction.
The researchers compared 41 species of shellfish by counting the nutritional density of each species, along with its impact on emissions. This created something of a marker of more and less nutritious fish, which could then be measured against their emissions output in each case.
The results broadly supported previous research findings showing that, on average, fish has a lower emissions footprint than other common sources of animal protein such as beef and pork. Interestingly, the results also revealed that in 50% of the fish species surveyed, protein levels were higher than in beef, chicken and pork.
These overall benefits of seafood can be summed up in one striking comparison from the study: beef scores below the average nutritional value of seafood, but has a higher emissions footprint than either species. surveyed by the authors.
However, the real interest of the study lies in fish species where exceptionally high nutrient levels overlap with low emissions, because they have the potential to reduce dietary impacts, without compromising nutrition, the researchers reason.
Here, they identified wild-caught salmonid species, including pink salmon and sockeye salmon, smaller wild forage species, such as mackerel and anchovies, and farmed bivalves, such as mussels and oysters, such as those with lowest greenhouse gas emissions per nutrient density ratio.
In fact, as the researchers calculate, these three groups account for “35% of the available nutrient density and contribute only 6% of production-related GHG emissions across all assessed species.”
And yet, even with these impressive credentials, these species are not the most widely consumed, far from it.
In fact, we harvest large amounts of the most nutritious and environmentally sensitive forage species, such as anchovies, only to grind them into powdered feed for farm animals to meet our protein needs.
Meanwhile, some of the fish that appear most often on our plates, like haddock and hake, which fall into the nondescript “whitefish” category, have some of the lowest nutritional scores.
For more evidence of our misuse of seafood, just consider octopus, squid, tuna, farmed and wild-caught shrimp: while these are some of the most desired and expensive seafood , they also have one of the largest emission profiles and are frequently weighed. at the lower end of the nutritional scale, the researchers found.
The highest emissions were generally associated with wild-caught species that require a large amount of fuel to catch, for example species caught using fuel-intensive long-distance fleets. The other driver of high emissions was how farmed species were fed, specifically how much food, energy, and filtration was required to raise species. For example, a species called Amur catfish ranked high in emissions, while farmed mussels ranked low because they require minimal inputs.
By distinguishing fish species for their nutritional benefits and emissions, the study helps identify action points for the future. Some of the fruits at hand would be to increase fuel efficiency and reduce energy inputs in aquaculture.
More difficult to achieve, but all the more important for it, would be to increase consumption of more nutritious and lower-impact fish species instead of red meat, perhaps with the help of new dietary guidelines that support the consumption of particular species.
That would also require us to move away from the deep-seated incentives and subsidies that currently encourage vessels to catch industrial quantities of forage fish just for animal feed, employing these incentives instead to encourage more sustainable harvesting of forage species to directly feed the humans.
With so many flashy meat alternatives on the market, we’re forgetting fish as a useful tool for steering our diets in the right direction, the researchers suggest. “While many hurdles need to be overcome, we have the potential to reshape seafood production and consumption toward species that optimize nutrition and minimize climate emissions.”
Ziegler et. Alabama. “Assessment of nutritional diversity of seafood along with climate impacts informs more comprehensive dietary advice.” Nature Communications Earth and Environment. 2022.
Image: ©Anthropocene Magazine
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