Salmon is a very popular fish, eaten by millions of people around the world. Due to its popularity, a lot of salmon now comes from fish farms rather than the wild.
This article compares wild salmon with farmed salmon and discusses the differences between them, including their environment and their diet.
Differences between wild and farmed salmon
Eating fatty fish, such as salmon every week has health benefits. 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
Salmon can be very crowded in fish farms.
Farmed salmon are fish stocks kept in netted pens. The farmers control breeding, feed them, and provide medicine if needed. Sometimes, the pens are very crowded and the salmon cannot swim very far.
Overfishing of the world's fish stocks has led to an increase in fish farming. Fish farming also keeps the price of fish lower.
Wild salmon live and breed in their native bodies of water. Humans have no control over their breeding, feeding, or health. Wild salmon swim long distances with no restriction.
Environmental and chemical contaminants affect wild salmon as well as farmed salmon.
2. Nutritional differences
Typically, wild salmon have fewer calories, saturated fat and vitamins A and D than farmed salmon, but contain more protein.
In both wild and farmed salmon, the omega 3 content will vary depending on what the salmon eats.
According to a 2017 review, wild salmon have higher levels of omega-6 fatty acids than wild salmon. Both farmed and wild salmon had comparable levels of an omega-3 acid called EPA, but farmed salmon had lower levels of the omega-3 acid DHA than wild salmon.
According to the Washington State Department of Health, "Farmed salmon fillets contain as many grams of omega-3 fatty acids as wild salmon because farmed salmon are fattier than wild salmon."
Omega-3s are important for:
- brain function
- eyesight
- sperm production
- energy production
- reduction of inflammation
Both farmed and wild salmon contain some compounds that are not good for the body. This is because salmon can absorb some chemicals and pollutants through their diet and their environment.
3. Differences in color
Salmon is a great source of protein, calcium, and omega-3 fats.
Wild and farmed salmon may differ in color due to their diet.
Wild salmon eat a lot of krill, crabs, and shrimp. These shellfish are high in a carotenoid called astaxanthin, which gives the salmon their pale pink-red color.
Sometimes wild salmon are white because of the way they process astaxanthin.
Astaxanthin is a potent antioxidant and anti-inflammatory that is essential for the general health of the fish. Fish farmers feed the salmon with pellet foods containing an artificial version of astaxanthin . The synthetic version of astaxanthin is not as strong as the natural version but is still beneficial.
Neither the natural and synthetic versions of astaxanthin are toxic to humans.
4. Persistent organic pollutants (POP)
According to an article in Diabetology & Metabolic Syndrome, POPs are human-made organic chemicals that take a long time to break down. POPs can build up 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 states that POPs can increase the risk of type 2 diabetes in humans. POPs do this by affecting insulin. Insulin controls the body's blood sugars.
Another study looking at POPs in indigenous communities where the people eat a lot of wild fish found an increase in type 2 diabetes.
POPs may also cause neurotoxicity. Neurotoxicity may increase the risk of Parkinson's and Alzheimer's disease.
A recent study found that wild Atlantic salmon contained higher levels of POPs than farmed salmon. This may be because their environment is uncontrolled and due to pollutants in the oceans.
A study looking at farmed Norwegian Atlantic salmon found levels of some POPs and pesticides were decreasing.
It appears that farmed salmon may contain fewer POPs than wild salmon. However, this is dependent on the type of fishmeal that farmed salmon eat. According to the Environmental Working Group (EWG), farm-raised fish contained 5–10 times more of a POP called polychlorinated biphenyl (PCB) than wild salmon.
If choosing farmed salmon, it is beneficial to find a reputable, responsible and sustainably raised source.
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