To my knowledge, the risks are relatively similar. I'm talking about the risk of disease or the deterioration of certain wildlife habitats near the rivers.
We don't practise open net aquaculture in Quebec. However, in the Maritimes, a drastic decrease in wild Atlantic salmon populations occurred after some open-net aquaculture facilities were introduced.
I don't know what the sensitivity differences might be between the different species of salmon, but salmonids are very sensitive to their environment.