Salmon on menu for king crabs
The use of salmon meal in feed for king crabs is showing promising results. A trial under Nofima’s direction points to the fact that salmon meal can replace traditional fish meal/herring meal without having a negative effect on growth or quality.
This means salmon producers can earn more from their salmon by-products, while creating the opportunity for increased production of the exclusive and highly demanded seafood product king crab.
Can become a world leader
One of the project participants, Norway King Crab AS, aims to be a world leader in the feed enhancement and sale of live king crabs. In order to succeed with capture-based aquaculture of king crabs, an important key factor is a feed that ensures low mortality and high growth. In order to grow and thrive, the king crab needs a protein rich diet, which can be provided by the salmon meal feed.
Salmon meal can be utilised better
Salmon by-products today constitute a large, but little utilised protein resource in feed for shellfish. Vital Seafood AS, which today produces fish meal from salmon trimmings, has a production capacity of approx. 3000 tonnes of meal per annum.
“In this project we wanted to replace as much of the traditional fish meal as possible with salmon meal, without having a negative effect on the growth, survival and quality of the king crab,” says Senior Scientist Sten Siikavuopio, who is responsible for the project. “Consequently, we set up a feeding trial with different levels of salmon meal in the feed, ranging from 25 percent up to 100 percent.”
No mortality or health-related injury linked to the use of salmon meal was observed during the three-month feeding trial. The crabs consumed all the feed types, but the scientists observed that the feed containing pure salmon meal was consumed quicker. This can indicate that the higher salmon protein content acts as a strong appetite stimulant in the crab feed.
Little or no difference
Further, the muscle growth in the king crabs was equally good among the crabs that were fed the feed containing 100 % salmon meal and the group fed traditional fish meal. An experienced taste panel from Nofima has evaluated the odour, colour, taste, texture and meat quantity of the fed king crabs. In order to gain a comparison, wild crabs were also evaluated. Even the experienced taste judges had to use all their knowledge to detect the difference. They too found no major difference between the fed crabs and the wild ones.
“We took samples during the experiment – at the start, in the middle and at the end. When the final samples were taken, newly caught crabs were evaluated in the same way as the fed crabs” says Siikavuopio.
For shorter feeding periods, such as in this trial, it is sensible to replace the herring meal with the cheaper salmon meal feed. However, the scientists recommend that for longer feeding trials a certain amount of the traditional fish meal is retained in the feed, as they still know little about the long-term effect. Nofima is now working on the technical properties of the feed in order to minimise the loss of feed.
This project was carried out by Nofima at Norway King Crab AS’s research station for king crabs in Bugøynes in Finnmark. Nofima was joined by Russian colleagues from the Russian Federal Research Institute of Fisheries and Oceanography (VNIRO) in Moscow.
This project was financed by Norway King Crab AS, Innovation Finnmark and Vital Seafood AS.