Farmed Salmon, Science Explains, Is One of the Most Toxic Foods in the World

While fish has always been considered a health food, science is now explaining why farmed salmon has become one of the most toxic foods in the world.

The growth of the farmed salmon industry has come at a great cost – not only for consumers, but for the environment, too. Salmon farms pose a very real threat to wild fish populations, according to to members of the Musgamagw Dzawada’enuxw and the Kwikwasutinuxw Haxwamis First Nations (1). The farms also make a negative impact on the surrounding communities that rely on wild salmon to thrive.

First Nation Impacts and Salmon Farming

Over the last 10,000 years, coastal First Nations of BC have relied on the sea to provide for their communities. Entire villages were fed off abundant runs of wild salmon, as well as other seafood like rockfish, abalone, clams, cockles, eulachon and other marine species.

The majority of First Nations in BC have made it clear that they don’t want fish farms in their traditional territories. Their main concern is the protection of wild salmon. Salmon farming puts at risk traditional food fishery resources, as well as protection of Indigenous rights to fishery resources as recognized by the Supreme Court of Canada.

If and when wild salmon stocks decline (as a result of salmon farming), there will be little left to harvest, and Indigenous rights to resources in traditional territories will essentially no longer exist (2).

Environmental Impacts of Farmed Salmon

Salmon farming is one of the most harmful aquaculture production systems. The use of open net-cages placed directly in the ocean means that farm waste, chemicals, disease and parasites are also released directly into surrounding waters, impacting marine life (3).

Salmon are carnivorous, which means they require a high percentage of protein derived from wild fish. In fact, more kilograms of wild fish are used to raise salmon than farmed salmon produced. This results in fewer wild fish stocks, contributing to the global wild fish depletion, thanks to over harvesting at biologically unsustainable levels.

Farmed salmon also escape more often than not, which creates competition for habitat and food between farmed salmon and wild salmon.

Another concern that affects juvenile wild salmon is the sea lice that proliferates in large amounts in farmed salmon populations. Sea lice that proliferates on salmon farms eventually spreads to surrounding waters, attacking baby salmon as they head out to sea.

Footage below shows just how harmful these farming practices have become:

Farmed Salmon Incredibly Toxic

When it comes to large-scale food production, fish farming is far from glamorous. This is confirmed in Nicolas Daniel’s documentary “Fillet-Oh-Fish,” which takes a critical look at the fish industry.

As noted by the producers of the film, “through intensive farming and global pollution, the flesh of the fish we eat has turned into a deadly chemical cocktail (4).”

The film starts off in Norway, looking at the chemicals used in fish farms. Below the salmon farms dotted across the Norwegian fjords, there is a layer of waste about 15 metres high, teeming with bacteria, drugs and pesticides. For renowned environmental activist, Kurt Oddekalv, this is confirmation of how salmon farming is a disaster both for the environment and human health.

Salmon farms are incredibly crowded – they can hold upwards of 2 million salmon in a relatively small amount of space. These crowded conditions result in disease, which rapidly spreads among the stressed salmon.

Pesticides used to stave off disease-causing pests (like sea lice), have a variety of negative effects, such as neurotoxicity. Toxicology researchers, Jerome Ruzzin, confirms the claims that Oddekalv puts forth. He’s tested a variety of different food groups sold in Norway for toxins, and, as expected, farmed salmon contains the greatest amount of toxins of them all – by an incredibly large margin.

Overall, farmed salmon is five times more toxic than any other food product tested. In animal feeding studies, mice fed farmed salmon grew obese, with thick layers of fat around their internal organs. They also developed diabetes (5).

Pesticides and Other Chemicals in Farmed Salmon

The pesticides used on farmed salmon also affect the fish’s DNA, causing genetic mutations – the film goes on to show examples of deformed cod. According to Oddekalv, about 50 percent of farmed cod are deformed as a result of pesticide use. When deformed female cod escape into the ocean to mate with wild cod, the genetic mutations and deformities are spread into the wild population.

Pesticides that have been banned for decades have concentrated in the fat of various marine life. This fat is used in the feed that fish farms use, which eventually leads to pesticide accumulation in the fat tissues of those who consume farmed salmon. Studies by the Environmental Working Group, along with those done in Canada, Ireland and the UK, have found that cancer-causing polychlorinated biphenyls (PCBs) exist in farm-raised salmon at 16 ties the rate of wild salmon (6).

Polybrominated biphenyl ether (PBDE), a chemical used as a flame retardant, has also been found in high levels in farm-raised fish. PBDEs are endocrine disruptors that are thought to raise one’s risk of developing cancer. According to scientists, high PBDE levels found in fish and humans can be blamed on fish feed, and increasing concentrations found in open oceans (which affects all marine life, wild or not).

Another study, conducted at the University of New York at Albany, found that dioxin levels in farm-raised salmon are 11 times higher than those in wild salmon (7). Dioxins are highly toxic, as they can be stored in the body for long periods of time. Their half-life in fat cells is seven to 11 years (7). Dioxins interfere with our reproductive, nervous, immune and endocrine systems, and also contribute to a higher risk of cancer.

The nutritional content in farmed salmon is also concerning. Farmed salmon contains over 14.5 to 34 percent fat, whereas wild salmon contains a slim 5 to 7 percent fat. Since toxins accumulate more readily in fat tissue, you can be rest assured that farmed salmon contains much higher toxin levels than wild.

Fish Meal Contamination

The reason for the higher contaminant levels found in farmed salmon is due to the feed given to them – a fish meal composed of ground fish and fish oil from only a few species of ocean fish. The fish being fed to farmed salmon accumulate toxins in run-offs from agriculture and industry that wind up in oceans. Since farmed salmon don’t really have an option to eat a wide-variety of fish compared to their wild counterparts, they are exposed to higher concentrations of contaminants.

For instance, in the documentary, “Fillet-Oh-Fish,” they describe how the fish pellet is created, which is later fed to farmed salmon and other farmed fish. The main ingredient, eel, is used for their high protein and fat content. The other fish included in the feed is a fatty fish from the Baltic Sea.

The Baltic is highly polluted, and some of the fish used have toxic levels of pollutants, which then get incorporated into the feed pellets. The toxicity of Baltic fish is taken so seriously that even the government recommends not eating fatty fish like herring more than once a week, and if you’re pregnant, to avoid fish from the Baltic altogether.

According to Swedish Greenpeace activist, Jan Isakson, the Baltic sea generates toxic dioxins as a result of run-off from a massive paper mill. Nine other industrialized countries surrounding the Baltic sea also dump their toxic waste into this closed body of water. These toxins accumulate in the fatty tissues of fish, making salmon, eel and herring particularly vulnerable, due to their fatty flesh.

Since these fish are not supposed to be fed to humans, they instead use them for fish feed. This makes farmed fish even more toxic than their wild counterparts, seeing as how their only food intake is that of polluted fish.

Omega-3 Options That Don’t Require Fish

While salmon is often praised for its omega-3 fatty acids, it’s far from essential. Most people don’t realize that omega-3s aren’t exclusive to fish, many plant-based foods offer them in the form of ALA (alpha-linolenic acid), which the body can convert (in small amounts) into EPA and DHA, the forms found in fish.

That said, you don’t need to risk eating contaminated or farm-raised fish to get your omega-3s. A well-rounded plant-based diet can provide ample ALA, and if you want to ensure EPA and DHA intake, algae-based supplements are a clean, sustainable alternative to fish oil.

Some of the best plant-based sources of ALA include:

• Algae such as spirulina and wakame (also rich in other trace minerals)
• Flax seeds
• Chia seeds
• Hemp seeds
• Pumpkin seeds
• Walnuts
• Leafy greens like spinach
• Cruciferous vegetables like broccoli, cauliflower, collards, and kale

The Bottom Line

Farmed salmon isn’t just a poor substitute for wild fish; it’s a full-blown environmental, health, and ethical crisis. From toxic feed and pesticide-laced flesh to the destruction of Indigenous food systems and marine ecosystems, the risks outweigh the benefits by a wide margin.

The decline of wild salmon stocks is more than an ecological concern; it’s a direct threat to Indigenous sovereignty, culture, and food security. And while industry voices continue to frame salmon farming as a “sustainable” solution, the science (and lived experience of coastal communities) tells a different story.

The good news? You don’t need to participate in this broken system to nourish your body. Opt for clean, plant-based omega-3s and algae-based EPA and DHA instead. It’s a simple choice that protects your health and sends a message. One that supports wild salmon, respects Indigenous rights, and helps keep toxic fish off your plate.