One out of the five salmons die in marine cage based fish farming in Norway. It cannot, according to the regulating body "Mattilsynet", continue. 

Farmed salmons are damaged and dying by applying many mechanical methods for removal of sea lice. This is one of the main findings in the Food Authority annual report for the 2016 which was published at March 27. "Parts of the fish farming industry is still struggling with the disease, high mortality rates, inadequate emergency response capacity and sea lice problems. The goal of good fish health and fish welfare could not be reached. " You may read more about the results in this newspaper article from Adressa 27.6.2017  (only available in Norwegian). The full report from Mattilsynet may be found here (in Norwegian). 
28.3.2017