This is an article about many misconceptions over wild vs farm raised salmon and, how much longer the salmon population can sustain itself.

http://www.sciencedaily.com/releases/2009/11/091124152803.htm

This is a second article about the leading causes of detrimental affects to salmon
http://www.telegraph.co.uk/science/science-news/3318467/Wild-salmon-hit-by-parasite-from-fish-farms.html