What's the difference between farm-raised salmon and wild salmon?

The amount of heart-healthy omega-3s in farm-raised salmon is the same as in naturally grown salmon. On the other hand, there is evidence that farmed salmon has significantly higher levels of contaminants like polychlorinated biphenyls (PCBs) than wild salmon. What's a salmon lover to do? PCBs are mostly concentrated in the skin of the fish and the fat directly underneath it, so avoid eating those parts of the fish. Opt to eat only one to two servings of farmed salmon a month, and search out stores that sell wild salmon. Also, try canned salmon. It's much easier to find in the wild form and less expensive than fresh.