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Salmon consumption has been linked to improved cardiovascular health and brain function. But not all fish are created equal. In the U.S., two-thirds of salmon are farm-raised. Compared to their wild counterparts, these fish are often less nutritious and have a larger environmental impact.
If you spot Atlantic salmon at the market or on a menu, chances are that it’s farm-raised. Less than 1% of Atlantic salmon is wild-caught.
Most farm-raised salmon is reared in open nets near the shoreline. Animals are fed salmon meal, an oil-rich blend of feeder fish and byproducts that makes them vulnerable to accumulating fat-soluble pollutants like PCBs and dioxins. On average, it takes four pounds of feeder fish to make one pound of salmon.
Crowded conditions promote disease. And antibiotics and waste products impact nearby marine life. And when farmed fish escape, they often breed with native salmon, compromising the genetic diversity of native stock.
In the wild, salmon accumulate omega 3’s when they eat microalgae, directly or by feeding on forage fish, like herring. Much like you or I, farm raised salmon get their omega 3’s from supplements. More than half the world’s fish oil output is consumed by salmon farms.
The feeder fish in salmon oil and feed often hail from the southern hemisphere, diverting food from poorer nations, depleting fisheries, and exposing farm-raised salmon to a wider array of contaminants.
Fortunately, there has been a move to farm fish in a way that is less damaging, through lower density pens, feeding regimes that require fewer feeder fish, and closed aquaculture systems on land.
Photo, taken on January 22, 2009, courtesy of Sam Beebe via Flickr.