Norwegian salmon giant SalMar has been forced to cull another 600,000 fish following a jellyfish attack at two more of its sites.

It follows the news that the company, the second largest salmon farmer in the world, had to cull approximately 1.2 million salmon in November following a jellyfish attack at one of its sites in Senja for reasons of fish welfare.

The scope of the jellyfish attacks has since spread and hit several other locations in central and northern Norway, said the company.