Sure. The rule of thumb that's emerging is that in the absence of salmon farms during the first two to three months of marine life for juvenile Pacific salmon, the prevalence of infection is approximately 5% or lower. That number comes from areas where there are no salmon farms. It does not come from areas before salmon farms were implemented there.
We only started studying this issue after the salmon farms were there and we started seeing these problems. So in order to get baseline numbers, we have to look elsewhere in British Columbia, where there are no salmon farms, and compare spatially--exposed versus unexposed--rather than before and after salmon farms come in.