All about salmon
Salmon farming, which involves raising salmon in containers placed underwater near shore, began in Norway about 50 years ago, and has since caught on in the United States, Ireland, Canada, Chile and the United Kingdom. Because of the significant decline in wild fish from overfishing, many experts see the cultivation 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 environmental ramifications with aquaculture.
Farmed salmon, less nutritious than wild salmon?
Farmed salmon is fatter than wild salmon, by 30 to 35 percent. Is this a good thing? Well, it cuts it both ways: Farmed salmon usually contains a higher concentration of omega-3 fats, a beneficial nutrient. They also contain a bit more saturated fat, which experts recommend eliminating from our diet.
Due to the intensive fish farming conditions in aquaculture, fish grown in the farm is subject to heavy antibiotic use to reduce the risk of infection. The real danger these antibiotics pose to 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 buildup of pesticides and other dangerous pollutants such as PCBs. Early studies have shown this to be a very worrisome issue, driven by the use of contaminated feed. At present the quality of feed is better controlled, but some contaminants continue to be detected, albeit at low levels.
Salmon farming can harm the marine environment and wild salmon
Some proponents of aquaculture claim that fish farming relieves pressure on wild fish populations, but most ocean advocates disagree. A study by the National Academies of Sciences found that sea lice from fish farming operations killed up to 95 percent of the young wild salmon they migrated.
Another problem with fish farms is the liberal use of drugs and antibiotics to control outbreaks of bacterial parasites. These primarily synthetic chemicals proliferate in marine ecosystems only from drift in the water column as well as from fish faeces.
Wasted food and fish residues also cause local nutrient contamination problems, especially in sheltered bays where ocean currents cannot help flush out the waste.
In addition, millions of farmed fish escape from fish farms each year around the world and mix with wild animal populations. A 2016 study in Norway reports that many of the wild salmon there now have genetic material from farmed fish, which could weaken 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 scale of the industry, improving conditions would be a start. Canadian ecologist David Suzuki says aquaculture operations can use completely closed systems that trap waste and do not allow farmed fish to escape into the ocean.
As for what consumers can do, Suzuki recommends buying salmon and other fish.
Whole Foods and other natural food and upscale groceries, as well as several involved restaurants, stocks wild salmon from Alaska and elsewhere.