Last month’s edition of Food X discussed how the fishing industry wreaks havoc on the ocean and on wildlife rebranded as “seafood.” Now let’s take a look at what happens in fish farms.
There’s a pervasive myth that aquaculture is a more sustainable option than taking wild fish out of our waters for food. The reality is that aquaculture’s simply a form of factory farming, with many of the same harms as terrestrial factory farms — and the industry has been rapidly expanding.
People often don’t consider that farmed seafood still comes from animals who, themselves, need to eat. And their food comes either from wild-caught fish or feed crops: Farmed fish consume about 1.2 trillion other fish, amplifying the pressure of industrial fishing.
It’s estimated that 90% of wild fish used as feed could be consumed by people. But fish used as feed are often exported, undermining food sovereignty by leaving local communities with environmental costs and no nutritional or economic benefits.
Salmon, the second-most-popular seafood in the United States, is a carnivorous species that, when farmed, relies on wild-caught fish. In the wild Atlantic salmon are powerful, beautiful fish who undergo an epic journey of hundreds of miles from freshwater rivers to feeding grounds in the North Atlantic Ocean; then they return to their home streams to spawn.
But in aquaculture they’re kept in crowded pens, subsisting on processed feed that’s typically made up of one-third to one-half wild-caught fish supplemented with corn and soy.
Fish farms, in general, are overcrowded and prone to polluted water and a high risk of disease. Pathogens, including antimicrobial-resistant strains, can be transmitted from sea pens to wild fish, threatening the health of those species and their ecosystems.
Like other factory farms, aquaculture can contribute to climate change at every stage, from the destruction of carbon-sequestering ecosystems like mangroves for farming shrimp (the most popular U.S. seafood) to the transport and processing of feed to the on-farm emissions and fossil fuel use. Certain types of aquaculture rank among the most emissions-intensive foods: Emissions from farmed catfish are on par with beef, and crustacean farming can generate higher emissions than pork production.
Despite these well-established red flags, the research on how seafood-heavy diets affect food-related emissions is thin compared to research on other types of food. Similarly, the science on meeting specific nutritional requirements — particularly omega-3 fatty acids — focuses heavily on fish, with more research needed on how alternatives, including plant-based sources, can fill the gap.
The Scientific Report of the 2025 Dietary Guidelines Advisory Committee — or DGAC for short — recommended “modest” intakes of seafood as part of a healthy diet. However, the DGAC wasn’t allowed to consider sustainability in its scientific review. If it had, it might’ve acknowledged the environmental cost of its recommendation.
This may leave you wondering what to put on your plate. The EAT-Lancet Commission report defines the Planetary Health Diet to improve human health, food justice, and environmental protection. It calls for 0 to 700 grams (one serving per day) of fish per week, highlighting that there are pathways to a healthy diet without fish. Eating farmed seafood lower on the food web, like seaweed, oysters, and clams, can minimize climate impacts and feed demands. Choosing a balanced, plant-based diet that reduces or eliminates seafood consumption is also a good way to reduce your dietary harm.
While for many of us this is a season of giving and abundance, it’s a good time to remember two things about food and farming. One, if everyone consumed the way even moderate Americans consume, we’d need several more planets to sustain us. And two, let’s practice a season of giving and gratitude by not wasting the planet we share.
Remember: Wildlife in the seas are part of important and vulnerable ecosystems, and for many Americans with plenty of food options, that may mean deciding not to eat fish at all.
Read More
“Blue foods” is the latest term that distances what’s on our plate from ocean wildlife. Learn more about what they are and how blue foods can be equitable, humane, and sustainable.
Learn more about different farmed species, their needs, and the toll of aquaculture at Faunalytics.
For the wild,
