I'm going to speak based on the results of the literature, which is completely independent and carried out by scientists without any kind of leaning toward any side.
The studies that stand out are those carried out by a group from the University of Alberta, led by Krkosek. What these mathematical studies show is that sea lice from farms can indeed have a great impact on the abundance of wild salmon populations.
There was another study carried out by one of his collaborators named Alexandra Morton that showed that if you put sufficient sea lice--and by this we mean in the order of four or five on a very small fish--this could lead to an over 60% chance of mortality, compared with fish that are not infected or are infected at a very low level, like maybe with one sea louse.
Now the question is whether this factor of sea lice, which obviously in laboratory situations has a major impact on salmonid mortality, translates into being the major factor in the field to the mortality. There are several other factors that I think could be involved in the high mortalities or the decline of wild salmon populations, one of them being global warming, as well as potentially other diseases.
However, this is where the studies of Krkosek--several studies have come out--are important, and it's important to understand the mathematics behind them. The mathematics basically show that for a linear system, which considers most of the factors, including one part that takes into account the remaining factors, sea lice loads on the small juvenile salmon can only be attributed in the majority of cases to the farms, not to any other thing.