An increase in damage caused by the spread of the Kudoa parasite in the meat of Norwegian mackerel has been causing increasingly noticeable damage over the last three years and especially this year, Italian research fellow Lucilla Giulietti said.

"We know practically nothing about the life cycle, only that Kudoa ends up in the mackerel meat, secretes digestive enzymes and breaks down the meat on freshly caught mackerel," Giulietti told IntraFish sister publication Fiskeribladet.

Scientists have observed degradation just 12 hours after harvest and the problem often grows up to 48 hours after harvest.