Mowi, the world’s largest producer of farmed salmon, has warned that a planned 40 per cent resource tax in Norway will lead to lower investment, job cuts and higher prices for the pink-fleshed fish all over the world.

Shares in Norwegian fish producers including Mowi, SalMar and Grieg Seafood plunged in September after its centre-left government said it would impose tax rises on the aquaculture and power industries, calling on them to share profits extracted from public resources with the rest of society.

The details of the tax, which will be applied retrospectively from the start of this year, are still being hammered out but the government said it intended to add a 40 per cent resource levy for fish farmers, which comes on top of a 22 per cent corporation tax.