Within minutes of the Oslo stock exchange opening on Wednesday last week, shares in the seafood sector began crashing. By the time the markets closed that day, $5.6 billion (€5.8 billion) in value had been wiped from some of Norway’s largest salmon companies.

The cause? The Norwegian government’s shock announcement on Tuesday night of a 40 percent tax hike on the country's salmon farmers. The proposed tax, which still must be approved by the Norwegian Parliament, is set to take effect beginning in 2023.