Farmed salmon nutrition declines as feed shifts from marine to crop ingredients

September 6, 2026 at 03:00 PM2 min

This digest was compiled by AI from multiple sources — links to the originals are below.

Farmed salmon's nutritional profile has declined as producers replaced marine ingredients with crop-based feed, according to new research. In Norway, the world's largest producer, marine-based feed ingredients fell from 90 percent in 1990 to about 23 percent by 2020. The shift doubled greenhouse gas emissions per kilogram of farmed fish in Europe and the UK from 2000 to 2020.

Key Facts

In Norway, marine-based feed ingredients for farmed salmon dropped from 90 percent in 1990 to about 23 percent by 2020.
The shift to crop-based ingredients doubled greenhouse gas emissions per kilogram of farmed fish in Europe and the UK from 2000 to 2020.
90 percent of the soy fed to farmed salmon in Norway comes from three Brazilian companies that have sourced soy from illegally deforested Amazon rainforest areas.
In February, environmental advocates and fishermen sent a letter to members of Congress opposing the Marine Aquaculture Research for America (MARA) Act.

Feed Composition Shift

Norway, the world's biggest producer of farmed salmon, saw marine-based feed ingredients fall from 90 percent in 1990 to about 23 percent by 2020. Advocacy groups determined that 90 percent of the soy fed to farmed salmon in Norway comes from three Brazilian companies. Each of those companies has sourced soy ingredients from illegally deforested patches of the Amazon rainforest. The shift to crop-based ingredients doubled greenhouse gas emissions per kilogram of farmed fish in Europe and the United Kingdom from 2000 to 2020.

Environmental and Nutritional Trade-offs

Researcher Hayek noted that it is difficult to attribute soy consumption to individual fish species. Cascada described the change as trading marine exploitation for land exploitation. Nutritionists and researchers say farmed fish, including salmon, will play a major role in providing protein. Environmental groups note the surge in salmon demand has disproportionately come from wealthy countries without nutritional deficits.

US Legislative Efforts

US lawmakers are trying to help the industry expand by passing legislation that would make it easier for salmon producers to obtain licenses to farm fish in offshore federal waters. In February, environmental advocates and fishermen sent a letter to members of Congress opposing the bill, the Marine Aquaculture Research for America (MARA) Act. Proponents of the bill say putting fish farms in deeper, offshore waters would reduce environmental issues caused by farming fish in sensitive, nearshore environments. Opponents say the legislation would enable a factory-farming model, much like the one that produces the vast majority of the world's livestock, in the open sea.