Fish farms boomed globally in recent decades — more than half the world’s seafood now comes from aquaculture — but it’s not a boom all environmentalists support. One argument that critics of industrial aquaculture make is that the fishmeal and fish oil used to make the feed for popular carnivorous species like salmon is not sustainably or ethically sourced. Yet it’s been hard to have a comprehensive understanding of where the fishmeal and fish oil comes from — until now.

In April, scientists published the first-ever open-source map of fishmeal and fish oil factories around the world. The team found 506 factories across some 60 countries, and in most cases were able to identify the companies that own them. The scientists, who were affiliated with the University of British Columbia (UBC) in Canada and published the paper in the journal Science Advances, also collected critical data on the types of fish many of the factories use and whether the raw material they process is whole fish or fish byproducts.

“Understanding where FMFO production occurs is essential for addressing its environmental, social, and economic impacts,” Lauren Shea, who served as lead author of the study while a UBC master’s student, said in a statement, using the common acronym for fishmeal and fish oil. “Knowing that, along with what species are being used and how it affects local environments and economies, can support the development of more transparent and responsible aquaculture practices.”

The factories press and cook fish or parts of fish. They grind up the solid material and turn it into a powder — fishmeal — and process the lipid-rich liquids into fish oil. Both are treasured ingredients in the feed of popular carnivorous species, such as Atlantic salmon (Salmo salar), sea bass (Dicentrarchus labrax) and shrimp. Prices have skyrocketed in recent years, especially for fish oil, nearly half of which ends up at salmon farms.

Fishmeal and fish oil production is controversial because it can incentivize the overexploitation of ocean ecosystems, depleting marine food webs, and negatively impact coastal communities that rely on fish for nutrition and livelihoods. Companies have been working to reduce the percentage of fishmeal or fish oil in the feed by developing alternative ingredients, but that effort has been countered by an increase in fish farms.

Environmental and human rights advocates frequently condemn the factories’ use of whole fish that could otherwise be consumed directly by local populations. The main whole-fish inputs come from small pelagic, or open-ocean, species, such as sardines, sardinellas, mackerels and anchovies. These oily fish are staples in low-income countries because they are, or were, widely available and inexpensive. Such fish are key sources of zinc, vitamin A, iron, calcium and fatty acids, especially for infants and young children.

“A lot of micronutrients are taken away from populations that need them most,” Nusa Urbancic, the CEO of Changing Markets Foundation, a U.K.-based NGO that has researched the industry extensively for many years, told Mongabay.

For the study, the UBC team gathered factory data on the 63 highest-producing countries, which together make up 99.8% of global fishmeal and fish oil production. Some data came from government reports; some came from the Marine Ingredients Organization, a U.K.-based industry trade group commonly known by its former acronym, IFFO; and some came from MarinTrust, a standard-setting certification body for marine-ingredient factories, which shares a London address with IFFO. (IFFO and MarinTrust have very close ties to one another, according to a 2024 Desmog investigation.) The team was able to verify the locations of the majority of the factory sites using Google Maps satellite imagery; most are located in industrial zones along a coastline. In a small number of cases, the only location data they could find on a factory was the city, province or country it was in.

Peru, the largest producer, had by far the most factories, with 125, the researchers found. Mauritania came in second with 42, though several other countries, including China, Chile, Vietnam, India, Thailand, the United States and Norway, had higher overall production than Mauritania despite having fewer factories.

While the feed-ingredient supply chains for aquaculture are global, the study indicates some geographic concentration. Most fishmeal and fish oil is sold to aquatic feed manufacturers like Cargill, Mowi, BioMar and Skretting, which mix it with other ingredients and sell it mainly to fish farms. Yet even with this intermediate step in the supply chain, the study shows that many of the fishmeal factories are based in the same countries that have a large number of fish farms, including China, Chile, Vietnam and Norway.

The study dealt not just with the location of the factories but also with the raw materials they use. In keeping with expectations, the UBC researchers found that pelagics less than 30 centimeters (12 inches) in length made up the majority of whole fish used in the factories. A more pressing question concerned the number of factories using fish byproducts versus whole fish, and on this matter there was a surprising finding that could on its face assuage environmentalists: the majority of factories were using, or at least were registered as using, fishery byproducts. Byproducts can come from processes such as canning, which treats heads and tails as waste. Finding a use for these discarded parts can decrease reliance on whole fish. The authors write that the use of byproducts in a “transparent and well-regulated manner … can represent an efficient waste-management strategy.”

Urbancic expressed wariness about the reliability of the data on byproduct use, given that much of it came from the industry, which she has long criticized. Changing Markets Foundation’s research indicates that there is considerable doubt as to whether a lot of the raw material that’s categorized as byproduct is indeed “genuine waste from fish caught for human consumption that would otherwise be discarded.”

In any case, the UBC researchers wrote that, in spite of the factory-by-factory breakdown, whole fish still constitutes most of the raw material used for fishmeal and fish oil. Shea told Mongabay that’s because that’s what the largest factories tend to use. That’s the case in Peru, where Peruvian anchovies (Engraulis ringens) are mostly processed whole, and in Mauritania, where the same is true for sardines and sardinellas.

The nutritional impact of the fishmeal and fish oil trade is pronounced in West Africa, where local people rely on small pelagic fisheries for food. In Senegal, local people have protested at least one fishmeal factory, while in the Gambia disputes over the role of fishmeal factories have led to protests and violence. Feedback, a U.K.-based NGO, has calculated, based on 2020 data, that Norway’s salmon farming industry alone drives the annual extraction of enough fish from the waters of Northwest Africa to provide 2.5 million to 4 million people in the region with a year’s supply of fish.

The aquaculture industry is expected to grow rapidly in coming decades, and with it the fishmeal and fish oil industry. Natasha Hurley, Feedback’s campaigns director, said the new UBC study could help draw attention to the pressure that fishmeal and fish oil production is putting on wild fish stocks, and to the global nature of the industry.

“This research provides welcome data on an industry that is largely operating out of public view,” she told Mongabay in an email. “With over 506 fishmeal and fish oil factories identified on every continent, it’s clear that FMFO production — driven mainly by demand from the aquaculture sector — is a global phenomenon and, as such, deserving of more scrutiny.”

Banner image: A fishmeal factory in India. Image courtesy of Changing Markets Foundation.

Norwegian salmon farms gobble up fish that could feed millions in Africa: Report

Citation:

Shea, L. A., Wabnitz, C. C., Cheung, W. W., Pauly, D., & Sumaila, U. R. (2025). Spatial distribution of fishmeal and fish oil factories around the globe. Science Advances, 11(17). doi:10.1126/sciadv.adr6921

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