The other problem is the fishmeal feed than farmed salmon are given. Much fishmeal contains high levels of polychlorinated biphenyls (PCBs). Depending on whose study you read, farmed salmon contain between 10 and 16 times the amount of PCBs found in wild salmon. Furthermore, farmed salmon is fattier and PCBs are mostly stored in fat. These issues, in combination with the constraints of the farm systems that Jim notes, makes wild salmon better. Also, because of the varied diet of wild salmon and, imo, because of the natural 'exercise' living entails for them, their flavors are brighter and more nuanced. Farmed salmon flavors, to me, are more one-note and somewhat flat.