A fish vet inspector in Norway, Aud Skrudland, has said the up to 60million salmon die of 300 million smolts put in farms in Norway in 2016. This does not include deaths of smolts
"The fish health situation is worrying. The
aquaculture industry is still struggling with salmon lice problems,
diseases, high mortality and inadequate emergency preparedness. The problems hinder the target of growth, she tells the site.
They report that 300 million fish are placed annually in the cages. In 2016, one in five of these fish died of health problems."
That means 60 million. This doesn't not include smolts dying during being raised, nor in transfer to the sites.
Auk goes on: "It [lice] is a natural parasite, but it increases in number of how much salmon it is within a geographical area, informs Skytland." This Google Translate version of the text means lice increase the more salmon are put in the water.
This is the link in Norwegian: https://www.an.no/laks/oppdrett/nord-norge/veterinar-bekymret-over-oppdrettslaksens-helse/s/5-4-658252?amp%3Bns_fee=0&%3Bns_linkname=editorial.share.article&%3Bns_mchannel=editorial.facebook&%3Bns_source=editorial.facebook.
Aud goes on to say that handled fish, for example, lice treatment preocedures, get reduced resistance and tend to succumb to one of a half dozen other diseases and die.
Asked whether she has seen any improvement in fish health in recent years, she said no:
""I wish I could say yes, but unfortunately I can not. The situation is worrying, the number of salmon that dies for various reasons has increased. Production growth has stopped and instead declined due to failure to handle the disease problems,"
So, after all these decades the Norwegian industry in Norway, has more problems than when it started. Remember the Hidra flu from decades ago? Things are even worse today.