The safety of farmed salmon relative to wild salmon is an significant debate. Wild and farmed salmon vary in their effect on the environment and in nutritional consistency.
Salmon is a very common fish which is eaten by millions around the world. Because of its success, most salmon now comes from fish farms rather than from wild ones.
This article compares wild salmon to farmed salmon, and explores their differences, including their climate and diet.
Differences between wild and farmed salmon
Eating fatty fish like salmon every week is good for the health. The 2015–2020 American Dietary Guidelines recommend eating 8 ounces (oz) of seafood per week
Salmon is an excellent source of:
- omega-3 fats
- protein
- vitamin A
- vitamin D
- calcium
We explore the differences between farmed and wild salmon below.
1. Wild and farmed salmon living conditions
Farmed salmon are stocks of fish that are kept in netted pens. The farmers manage the farming, feed it, and supply medicine if necessary. The pens are very crowded at times and the salmon can’t swim very far.
The overfishing of the fish populations around the world has contributed to a rise in fish farming. Fish farming keeps fish prices lower, too.
Wild salmon live and grow in water in their native bodies. Human beings have no power over their breeding, their eating or their welfare. Wild salmon swim long, unregulated distances.
Surrounding and chemical contaminants affect both wild salmon and farmed salmon.
2. Nutritional differences
Wild salmon usually have less calories, saturated fat and vitamins A and D than farmed salmon but have more protein in them.
The amount of omega 3 can vary depending on what the salmon eats, in both wild and farmed salmon.
Farmed salmon produce higher levels of omega-6 fatty acids than wild salmon, according to a 2017 study. Both farmed and wild salmon had similar omega-3 acid levels called EPA, but farmed salmon had lower omega-3 acid DHA levels than wild salmon.
“Farmed salmon fillets contain as many grams of omega-3 fatty acids as wild salmon, because farmed salmon are fattier than wild salmon,” according to the Washington State Department of Health.
Omega-3s are important for:
- brain function
- eyesight
- sperm production
- energy production
- reduction of inflammation
Both farmed salmon and wild salmon produce compounds which are not good for the body. That is because salmon are able to absorb certain chemicals and toxins through their diet and environment.
3. Differences in color
Despite their diet, wild and farmed salmon can differ in colour.
Wild salmon consume several crills, crabs, and shrimps. These shellfish are high in a carotenoid called astaxanthin which gives a pale pink-red color to the salmon.
Wild salmon are often white owing to the way they absorb astaxanthin.
Astaxanthin is a potent antioxidant and anti-inflammatory agent essential for the fish’s general health. Fish farmers feed salmon with pellet foods which contain an artificial astaxanthine version. The astaxanthin synthetic version isn’t as effective as the natural variety, but is still beneficial.
Neither the natural and synthetic versions of astaxanthin are toxic to humans.
4. Persistent organic pollutants (POP)
POPs are man-made organic chemicals which take a long time to break down, according to an article in Diabetology & Metabolic Syndrome. POPs may accumulate in animal tissue. Fatty fish can contain high amounts of POPs.
POPs are also known as:
- persistent, bio-accumulative and toxic (PBT)
- toxic organic micropollutants (TOMP)
POPs include:
- pesticides
- pharmaceuticals
- industrial chemicals
The same article notes that POPs will increase human risk of type 2 diabetes. This is done by POPs which affect insulin. Insulin controls blood sugars in the body.
Another research that looks at POPs in native communities where people eat a lot of wild fish found that type 2 diabetes had increased.
Even POPs can cause neurotoxicity. Neurotoxicity will increase the risk of Alzheimer’s and Parkinson ‘s disease.
A recent study found that wild salmon in the Atlantic had higher levels of POPs compared with farmed salmon. This may be attributed to uncontrolled environment in the oceans and toxins throughout them.
A research investigating farmed Norwegian Atlantic salmon has found declining levels of certain POPs and pesticides.
Farmed salmon may tend to have fewer POPs than wild salmon. But that depends on the sort of fishmeal that farmed salmon consume. According to the Environmental Working Group (EWG), in 2003 farm-raised fish produced 5–10 times more POP than wild salmon called polychlorinated biphenyl (PCB).
If farmed salmon are selected, selecting a reliable, responsible, and sustainably-raised source is helpful.
5. Heavy metals
Heavy metals like mercury can cause oxidative stress to the human body. Oxidative stress can cause cell damage which, in turn, can cause a number of health conditions.
Other heavy metals in fish include:
- arsenic
- cadmium
- lead
- mercury
One research found wild salmon in the Atlantic produce more mercury than farmed salmon in the Atlantic.
Both salmon have a certain amount of mercury inside their tissues. The salmon omega-3s can help to prevent damage caused by the mercury.
6. Animal drugs
Fish farmers also offer the salmon antibiotics and animal medicines to keep them safe. Some people have concerns that antibiotic use may increase resistance to human antibiotics.
Wild salmon are less susceptible to medications used by animals than farmed salmon.
Choosing wild salmon is the safest option for people who are worried about ingesting animal drugs.
7. Environmental and animal welfare concerns
Other issues relate to the effect that farmed salmon have on local ecosystems. Wild salmon thrive in their natural habitat, and do not increase contamination of the environment.
Fish farms can present a risk of pollution , particularly if they are located in low-current areas. This is because contamination caused by excrement of fish and unfed feed will enter the local environment and pollute the ecosystems below the netted enclosure.
The waste is spread by the water if deposited in high-current areas.
Some fishermen stock their farms with salmon that is not indigenous to the region. If the fish escape this can cause problems.
Escapeed salmon compete for food and mating with local species. Salmon that has escaped may also introduce disease and parasites.
The intensity of fish farming is also of concern. High-intensity productive fish farming also leads to overcrowding, which can lead to increased disease.
From an ethical and environmental viewpoint, when fishered sustainably, wild salmon is the best option.
How to tell the difference
Farmed salmon have a greater fat content than wild salmon. The fat may be visible, and farmed salmon may be shaped rounder than wild salmon.
Wild salmon are available seasonally and only in the summer. They may have a broader color palette as they have a different diet than farmed salmon.
Unfortunately, the distinction between wild and farmed salmon can not always be seen from reading the labels on the packets. The organization Oceana, found 43 percent of the restaurants and shops they surveyed were mislabeled salmon.
Takeaway
It’s difficult to determine whether farmed salmon are healthy to consume. In farmed salmon the amount of pollutants varies from location to location and depends on their diet.
Pollutant exposure is still a danger to wild salmon but research do not always capture the risk level.
Wild salmon are usually better nutritionally, and sustainably-fished salmon have a smaller environmental impact.
Wild salmon and farmed salmon are healthy to consume, and are excellent nutrient sources.
