Couple more thoughts here......

First, Roderick Haig-Brown imported and released Atlantic salmon for many years in the Campbell River to try to establish a self-sustaining run - and these efforts totally failed. This was only one of many experiments early in the last century conducted to try to figure out how to expand the range and angling opportunities for this king of sport fish, but it is probably the best known and is pertinent as that side of Vancouver Island is were most Atlantics are raised today. All of these million or so fish that have escaped over the years have had no better luck in establishing runs, and it is pretty unlikely that this will ever happen, as these fish appear to be unsutited for life in the Pacific wilds. Whether it is low disease resistance, inability to compete with wild salmon, or some other reason, Atlantic salmon just don't grow here.