Farmed Salmon: What Is Farmed Salmon & Is It Safe to Eat?

farmed salmon

From gathering seasonal nuts and berries to establishing intensive, large-scale factory farms, humanity has come a long way when it comes to food. While the new food system has opened up a wide variety of options for our dinner plates, it has also raised a number of health and ethical concerns. 

Perhaps one of the most popular concerns is about consuming farmed salmon. The global production of farmed salmon hit about 2.6 million tonnes in 2019, only to receive a major setback due to the coronavirus outbreak. The COVID-19 outbreak and new studies on the negative effects of salmon farming have prompted people to question whether farmed salmon is good for human health and the environment. As a result, wild salmon is often touted as a healthy and environment-friendly alternative. So, what exactly is farmed salmon, and is it safe to eat?

What Is Farmed Salmon?

Farmed salmon, also known as salmon aquaculture, involves different species of salmon—most commonly the Atlantic Salmon—being raised for food using intensive farming techniques. Fish who are destined for dinner plates are raised in tanks, ponds, or open-water enclosures using a variety of different methods

Farmed salmon begin their lives in hatcheries. When they are born, they are raised in freshwater tanks for up to two months. After a year or so, they are transferred to sea cages, where they are fed commercially-produced fish food often made of wild-caught fish. Salmon are kept unfed for a week before harvesting so that their digestive systems become completely cleared out, rendering them fit for human consumption.

Farmed Salmon vs. Wild Salmon

Wild salmon, as the name suggests, are caught from their habitat using commercial fishing techniques. There are some ways in which consumers can identify if salmon being sold in stores are farmed or wild. The most obvious way to tell is by looking at the label. Also, farmed salmon has more fat than wild salmon, which can be visible in the flesh. Finally, wild salmon can be pale-pink or even white, while farmed salmon is pink due to artificial astaxanthin present in their food. Astaxanthin is a chemical found in salmon food like shrimp. Astaxanthin is also artificially made and added to fish feed. The chemical is what gives farmed salmon their color. Though wild salmon is touted as a healthier alternative to farmed salmon due to lesser fat and fewer toxic chemicals, recent reports have shown both wild and farmed salmon contain polychlorinated biphenyls that are harmful to humans. 

Is It Safe to Eat Farmed Salmon?

There is growing consensus in the scientific community that farmed salmon are no longer safe for humans to eat. Farmed salmon often ingest harmful contaminants from the water they live in, which can be stagnant and dirty due to biological waste, as well as waste from chemicals that farmers use on them.

Farmed salmon present many additional health hazards for humans. Apart from the presence of hazardous chemicals, consuming farmed salmon could also cause irreversible damage to the nervous system, as well as increase the risk of cancer. The Food and Drug Administration’s nutritional data on farmed salmon also indicate that the fish contain high levels of sodium. 

What Is Wrong with Farmed Salmon?

Scientific studies over time have discovered a range of problems with the consumption of farmed salmon.

Antibiotics

Injecting salmon with antibiotics might seem like a good way to combat bacteria and disease, however, the reality is not so positive. One study showed an alarming level of antibiotic usage on farmed salmon. Between 2007 and 2017, the industry used about 5,500 tonnes of antibiotics, with each ton of fish having about 500 grams of antibiotics. Not only is this harmful to the fish, since they can develop antibiotic resistance and die, but humans who consume these fish also are at risk of being exposed to a range of drug-resistant bacteria. 

Astaxanthin

While wild salmon get their color by feeding on crustaceans like shrimp, farmed salmon have to be given synthetic astaxanthin in order to essentially dye their flesh pink. There are no health benefits from this practice apart from the visual appeal of pink salmon fillets lined up in seafood markets. Not only has scientific research not determined the safety of synthetic astaxanthin for human consumption, but the desire for a deep pink-red color means that excessive amounts of astaxanthin are often fed to salmon. High levels of astaxanthin could be detrimental to human health. 

Another similar chemical used by the salmon farming industry is canthaxanthin. Cheaper and more economical, canthaxanthin is often preferred over astaxanthin to cut production costs and increase profits. However, the harmful effects of canthaxanthin are well-documented, the most common being the accumulation of the chemical in human eyes, causing substantial vision loss and damaging effect on the neurosensory retina. It is also a potential cause of hyperactivity in young children. 

Heavy Metals

A recent study found a significant amount of arsenic present in farmed salmon. Consumption of arsenic from food and water not only puts humans at risk of diabetes and cardiovascular diseases but can also lead to cancer and skin lesions. 

Studies have also found the presence of lead, mercury, and cadmium in both farmed and wild salmon. Recent reports have also shown that some farmed salmon are exposed to radiation. Significant levels of polonium-210 in farmed salmon expose consumers to radiation and have consequential effects like lung cancer and genetic changes that can affect the cells’ ability to reproduce.

Nutritional Differences

Because of the varying diets of farmed and wild salmon, they differ in some key nutritional areas. The following table, supplemented by data collected from FoodData Central, the U.S. Department of Agriculture shows nutritional differences across various nutrients.

Nutrient0.5 fillet/198 g Farmed Salmon0.5 filler/198 g Wild Salmon
Water (g)128136
Energy (Kcal)412281
Total Fat (g)26.612.6
Protein (g)40.429.3
Carbohydrates (g)00
Ash (g)2.245.03
Fiber (g)00
Sugars (g)00
Calcium (g)17.823.6
Iron (g)0.6731.58
Sodium (g)11787.1
Fatty Acids (g, total saturated)6.041.94

This table shows that the presence of saturated fats in farmed salmon is much higher than that in wild salmon. Farmed salmon also contain more calories. From a nutritional point of view, farmed salmon do not yield many benefits to the body, much of which can be obtained from plant-based foods.

Parasites and Disease

Farmed salmon spend their lives in cramped, dirty tanks and are subjected to harsh chemicals and other contaminants. For example, farmed salmon are often exposed to cnidarian parasites, sea lice, flatworms, bacteria, and highly infectious diseases. One study discovered that the process of cleaning underwater farming environments causes irritation and damage to salmon gills and hemorrhages in the intestines. Sea lice chew into the infected salmon’s skin and mucus, creating open wounds that weaken fishes’ ability to maintain a healthy salt-to-water balance that is essential to their survival. Salmon farms across the world routinely face these deadly infestations. Because of this, many fish die. Treatments for this disease are short-lived due to sea lice developing drug resistance. Farmed salmon infected with sea lice who escape also pose the danger of spreading the disease to their wild counterparts.

Persistent Organic Pollutants (POPs)

Persistent Organic Pollutants (POPs) are harmful chemicals that cause significant damage to human health and the environment. Some common examples of POPs are DDT pesticides, industrial chemicals, polychlorinated biphenyls (PCBs), and industrial by-products like dioxins. The World Health Organization website cites a journal dated back in 2004 which found a significant presence of PCBs and dioxins in farmed salmon. More recent studies on Norwegian Atlantic salmon, Japanese masu salmon, and fish feed in Europe indicate the presence of PCBs and dioxins,  suggesting that these pollutants have accumulated in salmon farms over the years. Farmed salmon are also often contaminated with polybrominated diphenyl ether congeners (PBDEs), which increases the risk of thyroid cancer in humans and can cause thyroid dysfunction.

Ratio of Good-to-Bad Fats

One of the most hotly debated topics when it comes to eating fish surrounds omega fatty acids.

The fat composition in salmon usually includes Omega-3 and Omega-6 fatty acids. These unsaturated fats play a key role in brain development and a strong immune system. Typically, one should aim for a higher intake of Omega-3 fatty acids over Omega-6. However, farmed salmon contains about six times more Omega-6 fatty acids and just a little more Omega-3 than wild salmon. Research has shown that consumption of too much Omega-6 can cause detrimental effects on cells in the heart and blood vessels. Given that the ratio of Omega-3 to Omega-6 so heavily tipped, consumption of farmed salmon is sometimes linked to increased risk of a variety of diseases, including cancer, high blood pressure, heart attack, depression, and restlessness. 

It is hard to figure out the amount of omegas one is consuming when eating salmon. A report on Harvard Health cites studies that found Omega-3 content in wild and farmed salmon ranging from 533-717 milligrams per 100 grams of salmon. Furthermore, recent studies have shown that the ratio of beneficial Omega-3 fatty acids in farmed salmon has significantly fallen over the years, so consuming farmed salmon for health purposes could prove to be far less effective than consumers may have hoped. 

Wild and Farmed Salmon Living Conditions

Farmed salmon are kept in sea cages or netted pens. A typical pen can keep thousands of salmon cramped together. This results in crowding in dirty water, thus becoming a hotspot for disease. Some might say that wild salmon have it better when it comes to farmed living conditions since wild salmon live without all the chemicals, cramped environments, and artificial feed. However, farmed salmon spread disease among wild salmon. Moreover, with pollution spreading far and fast in oceans around the world, wild salmon have also been found to be contaminated with several harmful metals and chemical pollutants. 

Are Farmed-Raised Salmon Bad for the Environment?

The outbreak of diseases on salmon farms, overfishing, and global warming are creating extremely fragile ecosystems. On salmon farms, excess feed not consumed by the fish and laden with antibiotics, pesticides, and fish feces often makes its way into the oceans. This waste does not magically disappear. It often collects on the ocean floor, causing localized pollution, contamination of the marine ecosystem, and deprivation of oxygen to aquatic species. Salmon farms rely on ocean currents to clean up the waste. Pollution also affects local fish living near fish farms. Mostly consumed by coastal communities, these fish inadvertently become a health hazard.

Salmon are also carnivorous, meaning they need to be fed other fish as food. This results in more fish being caught from the wild, putting pressure on ocean fisheries.

Is Salmon Farming Ethical?

The life of a farmed salmon is “a life not worth living,” notes Faunalytics. Across the industrial fishing industry, the lack of stringent regulations incentivizes businesses to maximize profits at the expense of fish welfare. Salmon, who have evolved to migrate over distances as far as 9,000 kilometers, are restricted to small cages where they can barely swim for a few meters. Their cages are a breeding ground for parasites, and many fish also get attacked by sea lice, which poses harm not just to farmed salmon but also wild salmon, since sea lice can pass through farm cages and come in contact with wild fish populations. 

Every year, millions of diseased and dead farmed salmon are discarded as if they are not thinking and feeling beings, even though many scientific studies and journals have established fish sentience. According to the most recent research, fish like salmon can feel an enormous amount of pain and stress. Jonathan Balcombe, a renowned ethnologist, notes in his book What a Fish Knows that being farmed from birth to death deprives fish of their most natural instincts to play, explore, swim, and bond with their community. Many undercover investigations have revealed what happens to these sentient beings on salmon farms: bred in murky, overcrowded, and dirty tanks, the fish are kicked, thrown, slammed, and stomped upon. There is no medical care available if the fish are injured. Research has also found that fish like farmed salmon suffer from severe depression

Can Salmon Farming Affect the Wild Salmon Population?

Salmon farms have not yet resolved the issue of salmon escaping the farm and mating with their wild counterparts. Farmed salmon are genetically different from wild salmon because they are bred to grow quickly for human consumption. When wild and farmed fish breed together, the resultant offspring is not strong enough to survive in the marine ecosystem and ultimately dies.

The interbreeding of farmed and wild salmon has significantly threatened the wild population. Diseases affecting farmed salmon also infect wild salmon, putting their survival in further jeopardy. Wild salmon are crucial to a healthy marine ecosystem, and their dwindling numbers are becoming a threat to biodiversity. 

Conclusion

The detrimental impact of both farmed and wild salmon on our health, the environment, the fish, and the planet warrant a move away from consuming these fish altogether. Plant-based diets have all the essential nutrients, including the right amount of omegas that our body needs. Becoming a vegan for the animals and the planet is the best thing you can do to minimize one’s contribution to the needless exploitation of farmed salmon and motivate others to be a part of the change.