Study finds decline in omega-3 and toxins in farmed salmon over 15-year period.
A long-term study by Norway’s Institute of Marine Research has found that levels of marine omega-3 fatty acids in farmed salmon have declined since 2006, while concentrations of environmental toxins have also decreased.
The research, which analysed nearly 7,000 salmon fillet samples and 1,000 feed samples from 2006 to 2021, found that the most significant changes occurred between 2006 and 2014. The decline in EPA and DHA omega-3s coincided with a shift in feed composition, with a greater share of vegetable-based ingredients replacing marine raw materials.
Despite the decline, researchers said farmed salmon remains a good source of marine omega-3, vitamin D, and selenium.
The study also reported a reduction in levels of environmental contaminants such as DDT, dioxins, and PCBs in both feed and fillets. Concentrations of mercury, lead, and cadmium were found to be low or below detection limits in most samples.
The findings suggest a reduced health risk from toxins in farmed salmon, while highlighting ongoing nutritional shifts linked to feed changes.