All Atlantic salmon are farm raised. All supermarket filets labeled "Wild Atlantic Salmon" come from fish farms. There are currently no legal commercial fisheries in the Atlantic Ocean. 90% of available salmon on the US market comes from Atlantic fish farms. Of this total, 30% come from hatcheries and the rest are raised in offshore aquacultures called “open net pens."
In order to maximize space up to a million salmon are crowded into the net pens. Crowded conditions, a diet of corn and soy pellets, and massive amounts of salmon excrement in the water necessitate the administering of antibiotics and pesticides to combat disease and parasites such as sea lice. Copper sulfate is also added to the water to control algae accumulation on the nets. Many net pens are placed in estuaries that historically are home to native wild salmon runs. Enormous amounts of feed and excrement escape the net pens, along with the pesticides and antibiotics, polluting these estuarine environments. Broken nets have led to farm raised salmon colonizing and crowding out native wild populations. To protect its wild salmon runs, Alaska has banned net pen salmon farms.
Not having an ocean diet of crustaceans, algae and other sea nutrients, means farm raised salmon contain none of the omega oils and carotenoids that function as potent anti-oxidants. These carotenoids also act as a natural pigment on salmon meat, responsible for the distinctive red and pink color. The corn soy pellet diet of farm raised salmon results in meat dull gray or light brown in color.
Focus group research conducted by pharmaceutical giant Hoffman-La Roche concluded that consumers connect deeply colored red salmon meat with higher quality, freshness and a better taste. Consumers shown salmon fillets matching the hues on the Hoffman-La Roche SalmoFan™ Color Wheel preferred Color 33 by a two-to-one margin. To replicate this color in farm raised salmon, Hoffman-La Roche has produced an astaxanthin pigment (petroleum based) which is added to the food pellets.