The calculations in the paper show that even if lice levels on farm fish are controlled by medication, local wild fish still decline.

This is confusing. Apparently it is possible to control lice through medication. If that is so, why would all the discussion of lice in the preceding paragraphs matter? Is it a question of when the medication is applied and is it only being done after wild fish are infected? If so, why not just apply the medication sooner?

I have no dog in this fight, it just appears that either some of the calculations are SWAGs or it's apples and oranges. If the lice can be controlled, then there are other causes at fault.