The Japanese love Norwegian mackerel and are picky about the colour of the fillets, according to studies conducted by scientist Themis Altintzoglou and his colleagues. Photo: Audun Iversen/Nofima

Project Year 2016

Mackerel with the right colour, please!

 Industrial economics    Seafood industry  

The colour of the fillet can mean make or break for Norwegian producers trying to enter the Japanese market with pre-processed mackerel fillets.

Most of Norway’s mackerel is sold to Japan, where they eat 350,000 tonnes of mackerel a year. The Japanese buy whole mackerel from Norway and have it processed in Japan or China before it is delivered to retail outlets in Japan.

Now the Norwegian mackerel industry wants to fillet the fish themselves so they can sell products with a higher profit margin. To succeed, it is essential that production is adapted to what the consumers want.

Nofima has therefore conducted studies where Japanese consumers were asked about various factors, such as appearance and packaging.

Colour of the fillet

“What’s in the mackerel product package is much more important to Japanese consumers than what’s on the package,” says Themis Altintzoglou, who led the study.

“The Japanese want fresh fish and price is also decisive, but the most important factor is the colour of the fillet,” he adds.

The ideal mackerel fillet should be uniformly pale, without any red hues. The fillet should not have any blood in it, the skin should be shiny and the meat should not be flaky.

So how can we ensure mackerel fillets are always the right colour?

Stein Harris Olsen is researching how different fishing techniques and handling on board boats affect the quality of pelagic fish and has identified several factors that play a role.


“The basis for both the colour of the fillet and other quality criteria is laid during capture. Mackerel that spend a long time in the net become stressed, and blood is pumped into the muscles, giving the fillets a reddish hue and making them soggy,” Olsen explains.

Mackerel are caught with large nets and are pumped from the net into a cargo tank using refrigerated seawater (RSW). The cold water knocks them out and they die quickly.

In large catches, the fish spend a long time in the net before being pumped into the storage tank, resulting in exhaustion and in some cases injuries caused by stress and crowding.

For Japanese consumers to get Norwegian mackerel fillets with the right colour, the mackerel must be pumped gently and be promptly transferred to cold RSW.


More useful research results