Next time you head to the fish counter to buy salmon, consider choosing the wild variety instead of farmed. According to a report published in the journal Science, farmed salmon typically contain more potentially dangerous toxins than salmon caught in the wild, although some salmon farmers are making changes to improve their practices.
Researchers analyzed 700 wild and farmed salmon bought in 16 different cities in Europe and North America and found that farmed salmon contained unusually high amounts of industrial by-products, pesticides, and suspected cancer-causing agents known as polychlorinated biphenyls (PCBs). What causes the contamination? The food given to the salmon while in captivity is contaminated with PCBs.
How can you tell the difference between wild and farmed
The most reliable method is to ask the fish purveyor. If that's not possible, or if the seller isn't sure, check the color. You're probably familiar with the light-pink color of farmed salmon — wild salmon is a brighter, deeper shade of red. The price may also be a giveaway — farmed salmon is less expensive than wild salmon because it is more widely available.
Finally, don't let these findings stop you from eating salmon altogether. It remains a great source of heart-healthy omega-3 fatty acids. Just keep in mind that in most cases, it’s probably safer to "go wild." And if you can't find wild salmon, try getting rid of some of the fat — where PCBs accumulate — from farmed salmon by removing the skin and grilling the fish. Another convenient option is canned or pouched salmon, which is almost always from wild fish.