The Norwegian Food Safety Authority has approved a genetically modified (GM) canola oil for use in feed for farmed salmon. The canola was genetically engineered to contain healthy omega-3 long-chain fatty acids.

The GM canola, called NS-B50027-4, was developed as a land-based source of marine ("fishy") fatty acids. This is being touted as an environmental benefit since farmed salmon are normally fed on fish oil to boost their omega-3 levels.

Wild fish get their omega-3 from eating algae. But wild fish stocks are depleted and the price of fish oil has risen, meaning that the amount of fish oil in salmon feed has decreased markedly in recent years.

The "Aquaterra" omega-3 canola oil is being promoted as sustainable in the media by Nofima, a Norwegian research institute that conducts research and development for the aquaculture industry. Its scientists carried out research on Aquaterra omega-3 canola oil.

They concluded that when salmon have a diet containing the oil, they get more omega-3 in their flesh, better pigmentation and fewer dark spots — qualities designed to appeal to the health-conscious consumer.

Deformed butterflies

Taking the pressure off wild fish stocks by growing GM oilseeds that produce health-enhancing long-chain omega-3 fatty acids might seem like a good idea.

However, a study has found that these fish oils, novel in land-based ecosystems, cause wing deformities in butterflies.

The study was not on GM canola, but on the fish oils that such GM crops are engineered to contain.