1. The Title should be "Norway became a global salmon behemoth. Now it's facing the consequences". It fits the character limit, why change it?
2. A lot of the conditions for Salmon farming can be drastically improved or completely eliminated if they have done it further away in deep sea rather than coast. It just cost more.
3. China is rapidly improving their Salmon Farming so there isn't much to worry about for Norway. In 10 - 20 years time half of it will be gone.