(Beyond Pesticides, June 16, 2022) Farmed salmon serves as an inferior food source, accumulating more toxic chemicals in fatty tissue with fewer healthy nutrient properties based on a study from the University of Bergen, Norway and Alternative Medicine Review. However, the issue of toxic chemical contamination in fish dates back decades with investigations demonstrating high levels of persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs) flame retardants restricted or banned in the U.S. and U.K., polychlorinated biphenyl (PCBs), dioxin (a by-product of pesticide manufacturing), and ethoxyquin (a pesticide preservative in fish feed). The aquaculture industry (e.g., farmed seafood/fish) repeatedly faces sustainability issues, failing to adhere to environmental regulations and threatening marine health. Extensive use of pesticides in local marine ecosystems has induced coastal habitat loss and increased genetic and health risks to wild marine populations. Moreover, insecticides used to kill salmon parasites (e.g., fish lice) has led to widespread disease persistence and pest resistance. Marine species biodiversity is rapidly declining due to overfishing, global warming, pathogens, and pollution. Thus, further biodiversity loss can change aquatic and terrestrial ecosystem functions and reduce ecosystem services.
Food analysis results find the consumption of farmed salmon fillets contributes to higher rates of metabolic disorders, including diabetes and obesity. These farmed salmon also contain levels of toxins, including PCBs and dioxin, that are five times higher than levels in other tested foods. The report suggests the primary causes of farmed salmon toxicity stem from the toxicants in fish feed, like ethoxyquin, and environmental concentrations of the chemicals, whether from terrestrial sources or farmed fish itself.
Farmed fish, like salmon, use one of the most high-risk aquaculture practices, open-net pens in coastal and offshore regions. These pens allow easy exchange of waste (i.e., feces), chemicals (i.e., pesticides and pharmaceuticals), and parasites/diseases (i.e., sea lice) between the farm and the surrounding ocean environment. The discharge of waste, chemicals, and parasites/pathogens can have a disastrous impact on marine organisms and plants, disrupting ecosystem services. Generally, these pens are in relatively remote areas, somewhat “hidden” from public view. However, these fish live in very crowded conditions, unlike wild-caught fish. The fish consume food that may contain various pharmaceuticals (e.g., antibiotics) or insecticides to control diseases and pest infestations that frequently occur in these conditions. Furthermore, the farm pens can attract predators, such as marine mammals, that can tangle and drown in fish farm nets.
The U.S. permits the use of the pesticide ethoxyquin on fruit, vegetables, and meat meant for animal feed, with no intended uses on fish. However, fish feed manufacturing companies fail to address the use of ethoxyquin as a preservative to prevent oxidization/spoilage of fatty tissue.
Farmed salmon testing reveals levels of ethoxyquin are up to 20 times higher than levels allowed in fruits, vegetables, and meats. Despite there being no intended uses of ethoxyquin on food for human consumption, the chemical can pass to humans from contaminated food sources. Although claims suggest ethoxyquin has no human health effects, scientific evidence establishes that the chemical can induce DNA damage in human lymphocyte cells and chromosome aberrations.
Although current pesticide use and pollution contaminate both farmed and wild salmon populations, banned legacy pesticides like DDT, dieldrin, chlordane, and toxaphene continue to contaminate many major waterways, including shorelines where fishing is common. Legacy pesticides remain in the environment for decades as these products are relatively stable, with long half-lives. This slower breakdown rate and affinity to lipids (fats) allow these toxicants to accumulate in the fatty tissue of many marine species, including fish. Farmed salmon has a much higher fat content than wild salmon and thus has the potential to accumulate more lipophilic (fat-loving) toxic chemicals. Hence, the report advises individuals to consume wild-caught Alaskan salmon, not only due to the lower fat content but a shorter life cycle as well. Moreover, fish with shorter lifecycles, like small fish such as sardines and anchovies, tend to have a lower fat content and prove a better choice to mitigate chemical exposure. “With their low contamination risk and higher nutritional value, [these fish] are win-win alternative[s]. Other good choices include herring and fish roe (caviar), which is full of important phospholipids that nourish your mitochondrial membranes.”
The oceans are essential to human health and well-being, feeding billions, supporting millions of jobs, and supplying medicinal materials. However, environmental contaminants like pesticides and the subsequent effects of exposure, such as pest resistance, profoundly impact the ecosystem and its inhabitants. Pesticides are pervasive in all water ecosystems—from rivers, lakes, and oceans to glaciers in the Arctic, exacerbating the ubiquity and distribution of pesticide resistance among sea lice populations across the globe. Therefore, it is essential to understand how parasites may develop resistance to pesticides used to control populations in order to safeguard human, animal, and environmental health. Toxic pesticide use must end in order to protect the nation’s and world’s waterways and reduce the number of pesticides and resistant parasites found in our food, water, and wildlife resources. Learn more about how pesticides are hazardous to wildlife and what you can do through Beyond Pesticides’ wildlife program page.
There are many resources individuals can use to help gain knowledge and apply practices to avoid pesticide use and its adverse effects. These include news stories, local organizations, school pesticide policies, regulatory contacts, and least-toxic pest control operators. Organic practices can successfully eliminate toxic pesticide use. Replacing pesticides with organic, non-toxic alternatives is crucial for safeguarding public health and ecosystems from pesticide toxicity. Buying, growing, and supporting organic helps eliminate the extensive use of pesticides in the environment and from your diet. For more information on why organic is the right choice for consumers and the farmworkers who grow our food, see the Beyond Pesticides webpage, Health Benefits of Organic Agriculture.