“Farmed salmon are the most consumed farmed finfish in the Western world. The salmon-farming industry requires an enormous amount of food. And with salmon a lot of that food consists of other fish that are harvested from the wild. In an unimproved state, farmed salmon require as much as six pounds of wild fish, ground up and turned into pellet feed to produce one pound of edible flesh… and as salmon continue to be bred into a more and more efficient consumer of marine protein, that ratio is likely to drop.
But there is also a risk. The tamed-salmon genome is now markedly different from the wild-salmon genome. When tamed salmon escape into the wild (as they do in the millions every year) they risk displacing a self-sustaining wild fish population with a domesticated race that is not capable of surviving without human support. Salmo domesticus has been bred to eat a lot and grow fast in a controlled environment, but it has lost many of the fierce, determined traits that make a wild salmon able to swim against powerful currents, withstand fluctuations in temperature, and spawn in a river besieged by predators. Critics argue that escaped farmed salmon may outcompete wild salmon in some phases in their life cycle only to be unable to reproduce later on down the line. Some maintain that this could have a fatal impact on the long-term viability of wild salmon everywhere.”