While Norway’s controversial new 25 percent aquaculture tax finally has finally been implemented, understanding the full economic impact of the new tax on the country's fish farmers remains a bit murky.

In its recent third quarter report, salmon farmer Grieg Seafood reported it must pay a ground rent and production tax of about 4.5 percent of accumulated operating profit for its Norwegian operations during its third quarter, while salmon giant Mowi calculated it would receive a ground rent tax of around 8 percent on its Norwegian operations.