Oct. 20, 2026

What Your Farmed Salmon Ate

When Andrew Lewin studied marine biology at the University of Guelph in the late 1990s, his aquaculture professor made a prediction: one day, fish farms would supply half the world's seafood. That day has arrived. In 2022, aquaculture overtook wild capture fisheries for the first time and now produces about 51% of the world's aquatic animals.

The promise was simple. Farm more fish and you take fewer from the sea. A five-year investigation by The Outlaw Ocean Project, called Food for Feed, set out to test that promise by following what farmed fish eat. Maya Martin, a deputy editor at the nonprofit newsroom, joined Andrew on How to Protect the Ocean to walk through what the team found.

Farmed fish eat wild fish

Salmon, sea bass, sea bream and many other farmed species are predators. To grow quickly and deliver the nutrients people expect from seafood, they are fed pellets containing fishmeal, a dark-yellow flour made by cooking and grinding whole fish, and fish oil, its liquid counterpart.

More than two-thirds of farmed seafood depends on that feed. The fish that go into it are small, oily forage fish such as anchoveta, herring, sprat and sardinella. These are the same fish that tuna, seabirds, sharks and whales rely on. Globally, more than a fifth of wild-caught fish is used as a feed ingredient, mostly for aquaculture.

The investigation mapped more than 1,400 fishmeal factories across 64 countries. China, Peru, Thailand, India and Vietnam host the most. When the team assessed the fisheries those factories draw from, at least half of the species landed by fishmeal vessels were classified as overexploited or worse. In Maya's words on the show, aquaculture is in many ways making the overfishing problem worse.

Food colonialism in West Africa

The industry has long called these forage species "trash fish," as if nobody would eat them otherwise. The investigation found roughly 90% of the catch used to make fishmeal is edible for people.

In Senegal and The Gambia, sardinella is one of the most important sources of protein and a source of work for fishers and the women who process fish onshore. Fishmeal plants pay more than local processors, so there is a buyer for every fish. Maya described how this has driven up the local price of sardinella beyond the reach of ordinary buyers and pushed artisanal fishers out of work. Advocates call this food colonialism: high-value seafood for wealthier markets, produced by diverting affordable food from poorer regions.

The investigation links overfishing, alongside climate change, to migration from West Africa. Many fishers who can no longer make a living attempt the crossing to Spain's Canary Islands in wooden pirogues. Caminando Fronteras recorded 3,090 deaths on routes to Spain in 2025, most on that Atlantic crossing.

Living next to a fishmeal plant

Cooking thousands of tons of decomposing fish creates a stench that neighbours describe in vivid terms. One told reporters it smelled like a dead dog. Ian Urbina, the project's founder, had to wash all of his clothes every night while reporting in The Gambia, where the smell has driven tourists away from the town of Gunjur.

The smell carries real harm. It signals gases like ammonia and hydrogen sulfide, and its signature compound, trimethylamine, has been described by the Society of Chemical Industry as strongly toxic and carcinogenic. The team calculated that more than 9.5 million people live within a mile of a fishmeal plant. Technology like scrubbers and biofilters can contain odours, and plants in many lower-income countries don't install it because it's expensive and enforcement is weak.

Communities have pushed back. The investigation documented at least 80 incidents of civil unrest tied to fishmeal, most often in India, Peru and Senegal, sparked by stench, toxic waste dumped into waterways, and lost livelihoods. Some turned violent.

Dangerous work at sea and on land

Since 2018, more than 30 workers have died and over 440 have been injured at fishmeal plants worldwide. Rotting fish releases toxic gases, and workers in poorly ventilated holds and storage rooms have been overcome. Fishmeal is also flammable enough to spontaneously combust; plants and ships suffered at least 90 fires in the 1950s and 1960s alone.

The industry's answer to the fire risk was ethoxyquin, an antioxidant sprayed on fishmeal since 1967. It has since been linked to carcinogenic effects, and the European Union banned it in 2017. The United States still allows it in some animal feeds, including aquaculture feed. A review of more than 16,000 FDA records from 2018 to 2022 found trace amounts in imported shrimp, salmon and tilapia, all below the FDA's safety threshold, with seafood shipments more than 10 times as likely to contain it as other foods tested.

Reporters joined six voyages at sea, often by embedding with Sea Shepherd vessels supporting government patrols. Off The Gambia, they found four deckhands sharing a cramped room over the engine, too low to stand in, and captains who failed to log their catch as the law requires. Across the fleet of more than 2,400 ships the team assessed, fewer than a quarter had a unique vessel identification number, the ship equivalent of a licence plate. Without one, tracking who catches what becomes extremely difficult.

Fish farms in the desert

Some of the most surprising reporting comes from China. To move aquaculture away from polluted eastern coasts, the government has pushed fish farming west into Xinjiang and Tibet, a campaign it calls the "Blue Miracle." Farms tap groundwater beneath the desert and treat it to raise species like salmon. Xinjiang and Tibet now hold more than 1,000 fish farms.

Xinjiang is also where Uyghur and other Muslim minorities face mass detention, surveillance and state-sponsored forced labour. The US bans imports from the region under the Uyghur Forced Labor Prevention Act. Even so, the investigation traced salmon from a Xinjiang farm through an importer to Sysco, which distributes to cafeterias, public schools, federal prisons and military bases. Inspection of seafood imports is so limited that very little is ever checked.

Labels that miss the problem

The team assessed more than 550 seafood companies whose marketing makes strong sustainability or ethics claims. Over half had documented crimes or concerns somewhere in their supply chains. At least 80 of the fishmeal plants and supplier vessels investigated were certified by MarinTrust, and virtually all of them had crimes or concerns linked to their supply chains.

Maya explained why. Most certification checks focus on the farm and sometimes the processing plant. Inspections are often announced in advance, auditors rarely speak with crews away from the captain, and the process can become a paperwork exercise. Problems further up the chain, on the boats and in the fishmeal plants, go unseen. Consumer guides like Seafood Watch do strong work on ecological sustainability and have acknowledged the difficulty of monitoring labour conditions.

Every company and certifier named in the reporting was contacted before publication, and those exchanges are published in full on the project's Discussion page. Some opened internal investigations.

Bait to Plate

To connect these distant problems to everyday shoppers, the team built Bait to Plate, an interactive tool that maps supply chains across five stages: ship, plant, feed mill, farm and the brands and grocers that sell the seafood. You can pick a product and see exactly where a crime or concern entered the chain.

Maya hopes consumers use it to understand the hidden costs of cheap farmed seafood, retailers use it to find blind spots in their due diligence, and regulators use it to see how often these problems occur. As she put it, if journalists outside the industry could trace these links, companies with full access to trade data and paperwork can do better.

What you can do

Choose seafood that doesn't need feed. Farmed mussels, oysters and clams filter their food from the water around them, which makes them some of the lowest-impact seafood you can buy.

Buy local when you can see it come in. Seafood landed close to home is harder to hide abuses behind.

Look closer at labels. Treat certifications as one input and check the brands you buy on Bait to Plate.

Eat less, and value what you eat. Maya asks shoppers, especially in wealthier countries, to think about how seafood got to them so cheaply.

Support the groups doing the work. Maya named Amnesty International, Greenpeace, Oceana, Uyghur human rights organizations and local groups in fishmeal-producing countries. The project's methodology pages list many more by country.

The team's next investigation turns to krill, which the industry is increasingly harvesting from the Southern Ocean near Antarctica as a feed supplement, with little oversight and real risks for the whales that depend on it.

Takeaways

Aquaculture now supplies more than half the world's seafood, and most farmed fish eat fishmeal made from wild forage fish
At least half of species landed by assessed fishmeal vessels are overexploited or worse
Roughly 90% of fishmeal catch is edible for people, and diverting it hurts food security in places like Senegal and The Gambia
More than 9.5 million people live within a mile of a fishmeal plant, and the industry is tied to at least 80 incidents of civil unrest
Over half of 550+ seafood companies with strong sustainability claims had crimes or concerns in their supply chains
Farmed shellfish need no feed and are a lower-impact choice
Look up one farmed seafood product on Bait to Plate before your next purchase

Sources

Andrew Lewin

CEO

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