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Preventing malformations:

Production fish need a tranquil start

For production fish, a serene start to life raises their chances for normal development. This is the main conclusion of a major research project on malformations in cod and salmon.

Dr Grete Baeverfjord at her post at Nofima Marin. (Photo: Nofima) Dr Grete Baeverfjord at her post at Nofima Marin. (Photo: Nofima) Funded by the Research Council of Norway through the AQUACULTURE programme, five Norwegian research institutions have worked together to expand the overall understanding of an issue of great concern within the aquaculture industry: malformations. “We now know more than anyone in the world about malformations in production fish,” asserts Grete Baeverfjord, Senior Research Scientist at Nofima Marin. The project is profiled in the most recent newsletter from the HAVBRUK programme (“Nytt fra HAVBRUK” newsletter no. 1/2010, available in Norwegian only).




Dr Baeverfjord headed a collaborative project between Nofima Marin, Nofima Mat, the Institute of Marine Research, the National Institute of Nutrition and Seafood Research (NIFES) and the University of Bergen. “When it comes to salmon, we have made great strides, both in identifying specific causes and understanding the underlying mechanisms for how malformations occur. And although our knowledge for production cod is much less extensive, we are still in a position to make some concrete recommendations.”

Malformed cod

This winter, Norwegian fishermen have caught quite a few malformed cod – which are in all likelihood escaped production cod. Both the quality of fry and malformations in adult cod pose major challenges for the aquaculture industry.

“Our research indicates that cod would benefit significantly from a lower-temperature environment during first-feeding,” says Dr Baeverfjord. The same findings apply to salmon. Researchers believe that maintaining low water temperature during the early development phases is the most important preventive measure fish farmers can implement for both species.

However, in other areas cod and salmon show differences. “Cod must not be subjected to too strong a current in the tank. We recommend slowing down the current to prevent spinal column fractures. This is the second-most important measure for avoiding malformations in cod. For salmon, improper feed is the number two cause of abnormalities.”

X-ray of cod with a serious spinal malformation. (Photo: Nofima) X-ray of cod with a serious spinal malformation. (Photo: Nofima)

Simple measures can pay off

“Our conclusion is that both cod and salmon should be given a more peaceful start to life than they get now,” states Dr Baeverfjord, advising producers not to stress their fish too much during the fry stage.

Dr Baeverfjord is confident that the Norwegian aquaculture industry will follow researchers’ advice, as this will pay off financially in the long run. “We see that the major salmon-farming companies have already implemented our recommendations, which has helped to spur the growth of the salmon industry in recent years.”

European web portal

In a collaborative effort with scientists in other European countries, Norwegian researchers have established the web portal The website provides concrete advice to aquaculture producers on how to prevent malformations, as well as recommendations for protocols and more. The project has also resulted in a manual entitled “Control of malformations in fish aquaculture: Science and practice”, which may be ordered or downloaded on the website.

Written by:
Bård Amundsen/Siw Ellen Jakobsen. Translation: Darren McKellep/Carol B. Eckmann
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