Farm Raised Vs Wild Salmon: Is Farmed Salmon Bad For You?

Farm Raised Vs Wild Salmon
Image by Gingerbreadmedia from Pixabay

Estimated reading time: 10 minutes

As people are increasingly looking for information about the ethical and environmental impacts of their food choices, we examine whether eating farmed or wild salmon is more ethical, or if both are so problematic that we should be choosing something else entirely.

Farm Raised Salmon Vs Wild Salmon

Apart from the well-documented differences in color between farmed and wild salmon – which means fish farms actually add artificial coloring to the food to turn the fishes’ flesh pink – what else should we know about how these two systems operate? Well, both are bad news for salmon: On farms, they live in typical appalling factory farm conditions: at sea, there are no slaughter regulations to protect their welfare. And in terms of what these two systems mean for pollution, decimation of wildlife and our own health, it’s hard to say which is worse.

What Is Farm Raised Salmon?

Because the oceans are being decimated at an alarming rate by the fishing industry, salmon are increasingly being factory farmed – kept in intensive units, where hundreds of thousands of fish are crowded together in suspended pens. The fish suffer stress and disease in the same way other factory farmed animals do. There is a heavy environmental cost, too, as the waters around salmon farms become polluted with their waste, and infested with sea lice and the chemicals used to treat them and other diseases. This pollution threatens wild species and whole ecosystems. But first, we’ll start with the implications for our own personal health as well as for the wider public health.


Like many animals forced to endure the squalid conditions of a factory farm, salmon get sick. To try and prevent this – and also to promote faster growth – antibiotics are used. The problem is not so much that we ingest these when we eat the fish but more that when we overuse antibiotics like this, they stop working effectively, and antibiotic-resistant pathogens emerge. This is already a serious issue with 35,000 Americans dying each year and 2.8 million becoming sick. The impact of these “superbugs” will only get worse as we continue to waste precious antibiotics on propping up the failings of factory farming.

Cancer-causing Chemicals

Research shows that eating factory farmed salmon can increase our exposure to dioxins. These are environmental pollutants that accumulate in the fatty tissue of fish. So, the very ‘fish oil’ we are recommended to take for omega-3 could be harboring this damaging pollutant. According to the World Health Organization: “Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and also cause cancer.” It also has an immunosuppressive property that increases our chances of developing infections.

What about wild salmon? A recent study showed that wild salmon had even higher levels of dioxins than factory farmed fish. More broadly, the World Health Organizations lists the foods that contain the highest levels of dioxins as: dairy products, meat, fish and shellfish and says that “very low levels are found in plants”.

Risky Pollutants

It’s not just dioxins we should be aware of. Salmon also contains PCBs and pesticides, with research finding that wild salmon contains even higher levels than factory farmed fish.

PCBs – polychlorinated biphenyls – are highly toxic industrial chemicals that persist in the environment and accumulate in the flesh of fish, and then in people who eat them. They are also thought to be cancer-causing, and can affect the immune system and the brain. They pose serious health risks to fetuses, babies and young children. Despite being banned decades ago, PCBs are so ubiquitous in our environment that they are present in everything from dairy products to drinking water but the highest levels tend to be found in fish.

Our waters are now so polluted that wild and farmed salmon have also been found to be contaminated with many pesticides. including DDT, toxaphene, dieldrin, lindane, chlordane, hexachlorobenzene and mirex. The Centers for Disease Control and Prevention (CDC) says: “Human health effects from DDT at low environmental doses are unknown. Following exposure to high doses, human symptoms can include vomiting, tremors or shakiness, and seizures.”

Unsafe Contaminants

Mercury is described by the European Environment Agency as “a persistent threat to the environment and people’s health”. Naturally-occurring mercury is generally deemed not to pose any significant risk, but human activities have led to large amounts of it being released into the environment, with mercury in water being the primary cause of concern. It is highly toxic, and accumulates in the flesh of fish. Exposure to even small amounts can have serious health consequences, including on the nervous, digestive and immune systems, and can damage the development of unborn and new-born children. The consumption of fish is the main route by which people become exposed to mercury, and evidence suggests oceanic levels may rise as the planet continues to warm.

Nutritional Content

It’s difficult to be precise about the nutritional content of salmon meat, as that depends on what the fish eat. Wild salmon consume a range of small invertebrates while factory farmed salmon are fed processed food (that often contains soy grown on deforested lands) and the contents can vary farm to farm.

Generally, however, the nutrients associated with salmon meat are protein, omega-3, selenium, and vitamin D, all of which can be found on a plant-based diet where they come without those risky contaminants and pollutants.

Polyunsaturated Fat Content

Polyunsaturated fats include the essential fatty acids omega-3 and omega-6. Yes, salmon contains these but so do other foods! Omega-6 is found plentifully in plant-based foods and it is perfectly possible to get all the omega-3 we need, too, though we may need to pay a little more attention here. It can be found in walnuts, flax, chia and hemp seeds, edamame, kidney beans, soy oil and canola oil. So, it’s not difficult at all!

Is Farmed Salmon Bad For You?

There are many reasons to be concerned about eating factory farmed salmon, from the pollutants to the antibiotics to the heavy metals. Would we eat it? No, we wouldn’t. And we wouldn’t eat wild-caught salmon either.

What Are The Environmental Concerns

It’s not just our health that may be affected by the consumption of salmon, there is a significant health risk to our environment, too. Salmon farming destroys marine ecosystems through pollution and parasitic infections, with the global cost estimated at $50bn between 2013 and 2019. But catching wild-living fish isn’t the answer as that contributes to oceanic plastic pollution and climate change.


Fish held in factory farms will escape if they possibly can. In 2017, more than a quarter of a million salmon managed to break free from their pen on a Washington farm and out into the waters. It was dubbed a “disaster”. This was not the first time, or even the first time that year, that this had happened. When farmed fish go free, they may outcompete local wildlife, and transmit diseases to wild salmon and other animals. It’s a serious ecological problem, and yet we cannot blame the fish. Who wouldn’t try to escape from a miserable factory farm given the opportunity?


A 2021 report found that uneaten food and feces from farmed fish are serious polluters of the waters that the salmon pens are in. The report by Just Economic says: “Aquaculture activities are an interconnected part of the ecosystem in which they exist, and salmon farms make use of ‘free’ coastal ecosystem services such as clean water, appropriate temperatures, nutrient levels, and so on. They also contribute to their deterioration.”

Sea Lice

Salmon farming is concentrated in Chile, Norway, Canada, and Scotland. In Scotland alone, fish mortality has quadrupled between 2002 and 2019, with at least one fifth of the salmon’s deaths being attributed to sea lice. Lice infestation is just horrible for the fish who are effectively eaten alive by the bugs. One major contributing factor to this is the overcrowding and poor conditions on fish farms.

Transfer Of Disease

With farm pens located in wild waters, it is all too easy for lice and diseases to spread from farmed fish to wild fish. The most common ‘treatment’ involves harsh chemicals. Researchers in one recent Chilean study said that: “The pharmaceuticals currently used for the control of sea lice (cypermethrin, deltamethrin, azamethiphos, hydrogen peroxide) are applied by in situ immersion treatments, enclosing net pens using tarpaulin and then bathing fish with the pharmaceutical. After treatment the pharmaceuticals are released into the surrounding environment, exposing non-target species.”

Polluting waters like this is not acceptable. And these chemicals have been used so much that the lice are now building a resistance to them.

Destroying Marine Ecosystems

Those who buy farmed salmon in the belief that this protects the oceans are sadly mistaken. Not only do diseases and chemicals get out into the waters, affecting wild populations, but around 20 percent of all wild fish caught are fed to farmed fish. In west Africa, sardine shoals are heavily exploited with concerns that the population will collapse in the coming years. Headlines talk of global business “plundering Africa”.
A local small-scale fisherman said: “In four or five years, there won’t be any fish stocks left; the factories will close, and the foreigners will leave. We’ll be left here without any fish.”

Climate Change

So, while factory farming salmon is a serious problem for the environment, choosing wild-caught salmon brings its own significant problems. Commercial fishing is a reckless affair – it cannot target a single species but scoops up any animal unlucky enough to be in the way. This is called “bycatch”. Salmon fishing vessels have been known to catch and kill porpoises, whales and other large sea creatures. It’s desperately sad for those animals and it has a broader impact on us, too.

A 2019 study by the International Monetary Fund found that protecting large sea creatures is even more important than planting trees to prevent climate breakdown because these animals accumulate carbon in their bodies throughout their long lives. When they die, they take that carbon to the bottom of the ocean, where it is stored for centuries. But the fishing industry kills millions of these animals “accidentally” as bycatch every year.

Another way the industry contributes to climate change is through the trawlers themselves that carve through the ocean bed, destroying whole ecosystems and releasing still more carbon. The global fishing industry is as damaging to the climate as the entire aviation industry, according to a 2021 study.

Plastic Pollution

Most of the plastic in the ocean comes from the fishing industry. This causes the deaths of countless animals, including hundreds of thousands of endangered loggerhead turtles and critically endangered leatherback turtles who are drowned every year by longlines, trawler nets, gill nets and more, all discarded carelessly by the fishing industry. Worryingly, this is not set to improve. One study found that ocean plastic could triple by 2040 and outnumber fish by 2050.

How Ethical Is Farming Salmon?

We don’t believe a system of food production that causes serious harm to animals and the environment could ever be said to be ethical.

What Can You Do?

The best way to protect the oceans is through small changes to our food choices. You can get all the nutrients you need and all the flavors you love from plant-based foods. For those who really enjoy the taste of fish, there are many fish replacement products, including vegan salmon that taste … fishy.


The harm done by the global corporate food system to the planet, wild and farmed animals, and our own health is significant. We can build a better system – one that feeds the world, protects wild spaces and is good for our wellbeing – but we cannot rely on such a reckless industry to change. But we can drive positive change with our own choices, and we can start right away, choosing plant-based foods wherever we have the ability and opportunity to do so.

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