Salmon farming, which involves raising salmon in containers placed underwater near the shore, began in Norway about 50 years ago and has since caught on in the United States, Ireland, Canada, Chile and the United Kingdom. Due to the large decline in wild fish from overfishing, many experts see the farming of salmon and other fish as the future of the industry. On the flip side, many marine biologists and ocean advocates fear such a future, citing serious health and ecological implications with aquaculture.
Farmed Salmon, Less Nutritious Than Wild Salmon?
Farmed salmon are fatter than wild salmon, by 30 to 35 percent. Is that a good thing? Well, it cuts both ways: farmed salmon usually contains a higher concentration of Omega 3 fats, a beneficial nutrient. They also contain quite a bit more saturated fats, which experts recommend we phase out from our diet.
Due to the dense feedlot conditions of aquaculture, farm-raised fish are subject to heavy antibiotic use to limit risks of infections. The real risk these antibiotics may pose for humans is not well understood, but what is clearer is that wild salmon are not given any antibiotics!
Another concern with farmed salmon is the accumulation of pesticides and other risky contaminants like PCBs. Early studies showed this to be a very concerning issue and driven by the use of contaminated feed. Nowadays feed quality is better controlled, but some contaminants continue to be detected, albeit at low levels.
Farming Salmon Can Harm the Marine Environment and Wild Salmon
Some aquaculture proponents claim that fish farming eases pressure on wild fish populations, but most ocean advocates disagree. One National Academy of Sciences study found that sea lice from fish farming operations killed up to 95 percent of juvenile wild salmon migrating past them.
Another problem with fish farms is the liberal use of drugs and antibiotics to control bacterial outbreaks and parasites. These primarily synthetic chemicals spread out into marine ecosystems just from drifting in the water column as well as from fish feces.
Wasted feed and fish feces also cause local nutrient pollution problems, especially in protected bays where ocean currents are not able to help flush out the wastes.
In addition, millions of farmed fish escape fish farms every year around the world and mix into wild populations. A 2016 study conducted in Norway reports that many wild salmon populations there now have genetic material from farmed fish, which may weaken the wild stocks.
Strategies to Help Restore Wild Salmon and Improve Salmon Farming
Ocean advocates would like to end fish farming and instead, put resources into reviving wild fish populations. But given the size of the industry, improving conditions would be a start. Noted Canadian environmentalist David Suzuki says that aquaculture operations could use fully enclosed systems that trap waste and do not allow farmed fish to escape into the wild ocean.
As for what consumers can do, Suzuki recommends buying only wild-caught salmon and other fish. Whole Foods and other natural-food and high-end grocers, as well as many concerned restaurants, stock wild salmon from Alaska and elsewhere.
Edited by Frederic Beaudry