5 percent of farmed salmon deformed
May 10, 2005 � OSLO (Reuters) - Up to five percent of farmed Atlantic salmon in the world's top producer Norway suffer deformities perhaps linked to growing too fast or pollution, a scientist said on Tuesday.
Deformities � often a curved spine because young farmed fishes' flesh can grow too fast for their skeletons � also affect fish in other nations and other farmed species like rainbow trout or sea bream in pens from Norway to Chile.
"Our overall estimate for deformities in salmon is somewhere between 1-5 percent," said Grete Baeverfjord, senior research scientist at the Norwegian Institute of Aquaculture Research.
In some fish farms off Norway rates of deformities can exceed 25 percent while in others it is almost zero, she said.
"We're talking of millions of fish in total," she told Reuters in a break from a meeting in the west Norwegian city of Bergen trying to chart spinal disorders in fish farms.
The daily Dagbladet published researchers' photographs on Tuesday of some deformities including salmon with badly curved spines, jaws that cannot close or a lack of gills.
Some of the deformities are only slight, Baeverfjord said.
Norway is cooperating with a European research project with nations including Britain, Denmark and Italy to find ways to control the deformities, Baeverfjord said.
Reasons for the deformities were unknown but could include an imbalance of minerals in feed, polluted water, cramped pens or the wrong temperatures for water.
In some tanks for young fish, water is kept warmer than in the sea to promote faster muscle growth than in the wild as part of a bid to shorten the time to slaughter. With abundant food, the warm water may contribute to a bent spine as the pink flesh grows faster than the bones.
Deformed fish can be sold for human consumption, for instance as fillets or in pate.
"We're taking the problem very seriously," said Petter Arnesen, vice-president of Norway's number two salmon producer Fjord Seafood. "If we were sure what caused this we would be able to do something about it."