Salmon is an excellent source of nutrition whether it is farm-raised or wild, providing significant levels of important fatty acids and protein. However, due to their environmental differences, salmon raised in farms are not identical to those caught in the wild. Dietary and environmental differences can affect the nutritional value of farm-raised salmon, when compared to their wild alternatives.
Benefits of Salmon
Salmon provides omega-3 fatty acids, which have been linked to decreasing levels of cholesterol, blood pressure and promoting overall heart health. Salmon is also low in fat and high in protein, providing excellent nutritional value without contributing unnecessary calories. The American Heart Association recommends eating a serving of salmon once a week as a substitute for other sources of protein such as red meat, poultry and pork.
Farm-raised salmon are produced through controlled insemination practices and kept in saltwater pens. Producers feed them pellets that contain a mixture of soy, grains, fish oils and antibiotics. The general antibiotics are administered because farm-raised salmon live in close proximity to one another, increasing the chance for spreading any infectious disease that might occur. The main chemical added to farm-raised salmon is canthaxanthin, which gives their flesh a pink color. Wild salmon's pink color comes from natural substances found in their diet. Farmed salmon do not have the same freedom of movement, and therefore do not exercise as much as wild salmon. This, combined with their diet cause farm-raised salmon to have higher levels of fat and more calories than wild salmon.
A wild salmon's diet consists of smaller fish and its daily life involves high levels of exercise, swimming against currents and great distances. The result is a fish that is slightly leaner than farm-raised salmon. "Cooking Light" magazine reports that farm-raised salmon have nearly twice the omega-3 fatty acids as wild salmon, resulting in more fat and more calories. Omega-3 fatty acids are generally a "good" type of fat, but excess fats of any kind are unhealthy. Some find that wild salmon also has a better flavor and texture than farm-raised salmon.
A report by “Eating Well” magazine shows that farm-raised salmon generally have higher levels of mercury and polychlorinated biphenyl, or PCBs. PCBs are chemicals used in industrial applications that are often found in water supplies. They have been linked to neurological problems in children and negatively impact fetal growth. The level of these chemicals is low enough to not pose a health risk, especially in light of salmon's health and nutritional benefits. Pregnant mothers and young children, who are more sensitive to levels of mercury, may want to choose wild salmon when possible. The average salmon's level of PCBs is .027 parts per million, or ppm. The current FDA limit on PCB is set at 2 ppm. The Environmental Protection Agency recommends eating less than 8 oz. of salmon per month.