I'll answer the last question first.
In the Broughton Archipelago, we've been able to work out that the spatial sea lice footprint of an individual farm is about 30 kilometres, so in a radius of about 15 kilometres around the location of a farm, you will see elevated numbers of sea lice over what would naturally be there. If that same size of footprint holds for the Discovery Islands area, I would say that it is not possible for a juvenile salmon to migrate north on the inside of Vancouver Island without being exposed to a salmon farm.
On your first question, I agree that there are several explanations for why the Slice treatment in Nookta Sound failed. Resistance in sea lice is one possible hypothesis; there are others. It's not possible to distinguish among those hypotheses at the moment. The data is not here. Depending on that being an isolated event, that being unlikely, I think it depends on how much connectivity there is among sea lice populations on the coast there. We don't know how connected the population of sea lice in Nootka Sound is compared to other populations in B.C. If they're widely connected, then you'd expect to see the same treatment failures we saw there starting to happen elsewhere in British Columbia. At the moment, it's too soon to say.
As far as my wish list is concerned, I'd like to have accessible records on the number of fish per farm, as well as records of mortality events and disease outbreaks for all types of diseases for all farms in British Columbia. I think this is critical information that we need to look at to see if there is a reason why this could or could not be connected to problems in wild salmon productivity in British Columbia.