FRIDAY, Sept. 10 (HealthDay News) -- The U.S. Food and Drug Administration may soon approve genetically modified salmon for humans to eat, a prospect that is raising concern among some consumer advocates who consider the fish a threat to both health and the environment.

On Sept. 3, a scientific panel of experts that advises the FDA paved the way for the approval of genetically modified salmon, calling it "as safe as food from conventional Atlantic salmon."

The FDA's Veterinary Medicine Advisory Committee went on to say that the fish -- AquAdvantage Salmon developed by Waltham, Mass.-based AquaBounty Technologies -- contained the same amount of nutrients and had "no biologically relevant differences" from ordinary farmed Atlantic salmon. The FDA is scheduled to hold public hearings on the issue from Sept. 19 to 21.

If AquaBounty's salmon is approved, it would mark the first time a genetically modified animal has been approved for America's dinner plates and restaurant menus.

That's what worries consumer advocates, who say approving the salmon is opening the door to all sorts of genetically engineered animals, such as pigs and other mammals.

The FDA is regulating genetically engineered animals as it would a new veterinary drug, which means that much of the research and information about the product is being kept confidential, said Wenonah Hauter, executive director of Food & Water Watch in Washington, D.C.

"We don't know if it's safe for humans to eat and the only research that has been done was done by the company," according to Hauter. "The FDA is an under-resourced agency that has had so much trouble with the regulatory system for foods -- we've had tainted eggs, poisonous peanuts and other contaminations -- and is now taking on something in a very non-transparent way."

Recently, Food & Water Watch was joined by 30 other animal welfare, consumer environmental and fisheries groups, including the Sierra Club, which issued a statement citing concerns that the fish could escape and pose an environmental threat. Previously, another group of consumer advocates and others warned that "transgenic fish" could introduce new or unknown allergens into the food supply.

AquaBounty creates its salmon by taking a growth gene from the Chinook salmon and a gene "promoter" from the ocean pout, another type of fish, said John Buchanan, AquaBounty's director of research and development. The pout gene promoter simply turns on the Chinook salmon growth gene, and is not actually expressed [active] in the modified fish. The resulting salmon grow to market weight about twice as fast as ordinary Atlantic salmon, though they don't get larger overall.

While it typically takes about three years for salmon to grow to market weight, AquaBounty's salmon get there in about 18 months, Buchanan said.

To safeguard the environment, Buchanan said the eggs will be treated so that all fish that grow from them will be sterile females. That means they will not be able to reproduce, nor will they come into contact with males to reproduce with, said Buchanan, whose firm would sell the treated eggs.

While farm-raised salmon is typically grown in ocean-based tanks, the genetically modified fish will be grown in land-based tanks, also minimizing the chances of escape, he said.

"We have done a tremendous amount of work geared toward regulatory approval to show that the fish is healthy and safe," Buchanan said.

Genetically modified animals have been produced since the 1970s, according to background information in the FDA's briefing materials, but none have been approved for human consumption.

Currently, genetically modified soybeans and corn are being sold for people to eat.

AquaBounty said bringing the salmon to market would take at least 18 months after approval. Farmers that want to grow the fish will also need FDA approval of their facilities.

Buchanan also believes that, if approved, the fish could help reduce pollution, disease and other problems associated with saltwater fish farms, as well as provide an alternative source of seafood to help reduce the impact of overfishing.

One question for consumers is whether packaging will be required to specify that the salmon is genetically modified. The FDA will consider that issue during the public hearings.

More information

Read what the U.S. Food and Drug Administration advisory panel had to say about genetically modified salmon.