Eating Seafood Can Reduce Your Carbon Footprint, But Some Fish Are Better Than Others
By Amy McDermott
Food is expensive. Not just for pocketbooks, but for the planet. Worldwide, more than 25 percent of greenhouse gas emissions come from food production. That's methane belched from cows and nitrous oxide escaping from soils, as well as fossil fuels burned by tractors, fishing boats and rumbling transport vehicles. Some foods cost more than others.
Seafood has a smaller carbon footprint than other animal proteins, on average, because fishing doesn't require farmland or care of livestock. But even among seafoods, fish and shellfish can have varying impacts.
So what's the best choice? Small schooling species, like anchovies and herring, are the most sustainable options, experts say, based on energy use and emissions of their fisheries. There's no free lunch. The question is, what can the planet afford?
Fishermen unload a catch of anchovy and sardines in Ayvalik, Turkey. OCEANA / María José Cornax
Small schooling fish are low impact because catching them doesn't burn much fossil fuel, the major source of emissions for fisheries.
Ninety percent of the greenhouse gas emissions associated with wild seafood come from fuel use, said Peter Tyedmers, who studies the environmental consequences of food systems at Dalhousie University in Halifax, Nova Scotia.
"If you think about fishing, where does fuel get burned?" he said. "On a fishing boat, it's driving the engine. Some fisheries guzzle more gas than others. It depends how long and how hard the engine works."
Fisheries targeting anchovy, mackerel and similar fish are the most fuel efficient, according to a 2015 study coauthored by Tyedmers. They average less than 80 liters of fuel per ton of catch when fishermen use purse-like nets to surround huge schools of the fish. Because these species swim in dense aggregations, fishermen can locate a swarm, throw a net around the whole thing and pull up thousands of fish in one trip.
Compare this to crustaceans like Australian Tiger prawns or Norway lobster, which can burn more than 10,000 liters of fuel per ton of catch. That's because it takes a lot of gas to drag a heavy prawn net through the water, as does motoring from one lobster trap to another. Scooping up a whole school of fish at once is much more fuel efficient.
Conservation status matters too, said Nathan Pelletier, an ecological economist and industrial ecologist, specializing in food system sustainability at the University of British Columbia. When populations are healthy, there are more fish in the water, so it takes less time and less fuel to fill a net. Overfishing leaves fewer fish out there, so it takes more time and energy to catch the same amount.
"Abundant fisheries, from a climate change perspective, will be less greenhouse gas intensive," Pelletier said. "All else being equal, the more fish there are, the less energy we will have to invest in chasing them around and catching them."
A school of sardines rushes around a diver in Tañon Strait, the largest marine protected area in the Philippines. Dense aggregations of little fish make them a fuel-efficient target for fishermen in other areas. OCEANA / Ferdinand Edralin
On the Half Shell
Farmed mollusks may be another climate-conscious seafood, according to a forthcoming study by ecologist Ray Hilborn, at the University of Washington in Seattle. That's because these shellfish don't need to be fed; they can filter sustenance from the water instead. Animal feed can be a huge consideration when it comes to a farm's carbon footprint.
"From a climate change perspective, what you feed and how much you feed matters a lot," said Tyedmers. "In aquaculture, the big generalization is your greenhouse gas emissions are overwhelmingly driven by your feed inputs."
Farmed fish eat a combination of plant and animal parts, like ground up soy or corn, chicken feathers, animal bones and blood. Each ingredient takes energy to grow or catch, and then more energy to process into pellets or flakes. Farming mollusks sidesteps that issue, because they're filter-feeders, no pellets required.
Hold on though, Pelletier said. The jury is still out on mollusks. They don't need to be fed, but they do take effort to seed, harvest and process for human consumption. Considering the amount of meat on a mussel or oyster, it's a low edible yield for the effort.
Farmed mollusks may look good in theory, but Pelletier says he'd be cautious to endorse them, because "it's mostly shell."
Mussel farmers poke through the rows in Thailand. MKeerati / Shutterstock
Of course, to reduce carbon footprints as much as possible, the best bet is to eat veggies. On average, eating plants has a smaller footprint than eating animals, said Friederike Ziegler, who studies sustainable seafood at the Research Institutes of Sweden, in Gothenburg. But among animal products, seafoods are some of the best, she said. And among seafoods, little fish are the best of the best.
In Sweden, where Ziegler lives and works, the government recommends eating seafood two to three times per week. Most Swedes eat less than that. Small, schooling fish like herring are famously popular in Scandinavia, but even in Sweden, Ziegler said people could eat more fish.
Not everyone can switch to veggies, for both cultural and nutritional reasons. Wild sustainable seafood is the best option, in many parts of the world. When it comes to changing diets, "we have to think about solutions that are culturally appropriate and feasible within their specific contexts," Pelletier said.
Atlantic horse mackerels race beneath Oceana's Ranger at Dacia seamount, Spain. Small oily fish like mackerel are some of the most carbon-conscious seafoods. OCEANA / Carlos Minguell
Climate change looms large over the future. To fight it, think like an ocean predator. Dive into the little fish, with big potential for good.
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EcoWatch Daily Newsletter
By Naomi Larsson
For centuries, the delicate silver dove has been a symbol of love and fidelity.
Biodiversity and Habitat Loss<p>Their near extinction is a symbol of the <a href="https://www.dw.com/en/global-biodiversity-outlook-targets-extinction-summit-new-york-pledge/a-54932895" target="_blank">biodiversity crisis</a> in the UK, largely driven by habitat destruction. Britain is now one of the countries with the most <a href="https://www.wwf.org.uk/future-of-UK-nature#:~:text=The%20UK%20is%20one%20of,than%20half%20are%20in%20decline" target="_blank">depleted nature</a> in the world according to the World Wildlife Fund. Half its plant and animal species are in decline and more than <a href="https://www.rspb.org.uk/about-the-rspb/about-us/media-centre/press-releases/let-nature-sing-wales/#:~:text=a%20natural%20tragedy.-,Over%2040%20million%20birds%20have%20vanished%20from%20UK%20skies%20in,unaware%20of%20the%20impending%20danger" target="_blank">40 million birds</a> have vanished in just half a century.</p><p>"[Turtle doves] are the canary in the [coal] mine because there are all these other species before it and after it," said Tree. "It's an umbrella for all the other species that are heading that way."</p><p>Turtle doves migrate south through Europe to sub-Saharan Africa between July and September, ending up in dry woodland and farmland areas of countries like Mali and Senegal for winter. </p><p>Droughts in West Africa and the Sahel region are believed to have contributed to the fall in turtle dove species recorded in northern Europe, with low rainfall reducing supplies of the seeds and insects the birds rely on for energy for the long journey home.</p>
Conservation and Farming<p><a href="https://www.operationturtledove.org/" target="_blank" rel="noopener noreferrer">Operation Turtle Dove,</a> a partnership project of charities including the Essex Wildlife trust, works with landowners and farmers to actively build turtle dove habitat.</p><p>Outten works with <a href="https://www.ebws.org.uk/birdsites/blue-house-farm-ewt-north-fambridge" target="_blank">Blue House Farm</a>, a 660-acre nature reserve in the UK county of Essex, where they have replicated weedy fallow plots. </p><p>"We work on it every year to make sure it's in the condition it needs to be with plants such as clovers and black medic," Outten said. "These plants are native to the landscape and produce the seed the birds feed on." </p><p>The birds eat a wide range of seeds from various plants that would have been abundant 50 or 100 years ago, added Guy Anderson, program manager for species recovery with The Royal Society for the Protection of Birds (RSPB). </p><p>"But it's simply true that with the gradual process of <a href="https://www.dw.com/en/farming-without-pesticides-how-can-we-make-agriculture-greener/a-52216796" target="_blank" rel="noopener noreferrer">intensifying our agricultural production</a>, the availability of those seeds has dropped and dropped," said Anderson.</p><p>Part of the project includes supplementary feeding — providing sources of food in the form of seed or grain. Under the Countryside Stewardship Scheme in England, farmers can receive financial support to create a turtle dove habitat. </p><p>Though they haven't recorded an increase in doves across the sites in the four years of working on the project, Outten said they are seeing improvements in how landowners and farmers manage habitat for the birds. </p>
A Turtle Dove Haven<p>The 3,500-acre Knepp Estate in West Sussex is another project taking a different approach and one of the few places where turtle dove numbers are increasing.</p><p>Isabella Tree and her husband Charlie Burrell converted their intensively farmed land into a rewilding project almost 20 years ago. They have let the land return to nature.</p><p>Just one year after they'd finished <a href="https://www.dw.com/en/uks-most-talented-architects-are-not-human/a-35952128" target="_blank">rewilding</a> the southern part of their property, they heard turtle doves for the first time. It's now a breeding hotspot for the birds with an estimated 19 pairs. Knepp is also home to <a href="https://www.rewildingbritain.org.uk/rewilding/rewilding-projects/knepp-estate" target="_blank" rel="noopener noreferrer">2% of the UK's population</a> of nightingales. </p><p>Tree is critical of supplementary feeding schemes that, in her view, are short term. She questions the chances of turtle doves getting to feed on scattered seeds before other mammals eat them first.</p>
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