Usually Atlantic salmon do not grow during the winter and take three years to fully mature.

But by implanting genetic material from an eel-like species called ocean pout that grows all year round, US scientists have managed to make the fish grow to full size in 18 months.

They hope that the sterile GM salmon can offer an efficient and safe way to breed salmon in fish farms, so that the wild fish can be left in the oceans.

US watchdog the Food and Drug Administration is currently considering whether the GM Atlantic salmon, called AquAdvantage, is safe to eat. The fish could be on supermarket shelves within a year.

But environmental campaigners question whether the GM material is safe for humans to consume and fear the sterile salmon will mutate in the wild and be able to breed.

At the moment only GM crops like corn or soy are available for human consumption. Also the Daily Telegraph revealed recently that most animal products available in supermarkets, like meat, eggs or dairy, are from livestock fed GM.

But despite the creation of a GM mouse as early as the 1980s, the idea of eating modified animals does not appeal to the public.

AquaBounty, the Massachusetts company behind the GM salmon, say the fish will be sterile and therefore poses no risk to the wild.

The AquAdvantage would also be a much more energy efficient way to produce a nutritional food source, they claim.

Another project at the University of Guelph in Canada is developing a pig bred to digest food more effectively.

But Lord Melchett, policy director at the Soil Association, said the new technology is not worth the risk.

"Once you have bombarded an animal with other genes, the DNA is unstable, and there is no guarantee these fish remain sterile. It poses far too great a risk to wild salmon. A fish that grows that quickly is likely to lose some of its environmental benefits. There is no such thing as a free salmon lunch and we will pay the price," he said.

It will be a huge victory for the biotechnology industry if a GM animal becomes available for human consumption.

But in the UK, the public remains suspicious of 'Frankenfoods'. A Food Standards Agency survey to find out what the public think of the new technology is currently stalling after two leading academics resigned in protest at the government body's 'pro-GM' stance.