Genetically engineered salmon that grows twice as fast as the conventional fish appears to be safe, an advisory committee told the Food and Drug Administration Monday. But they argued that more testing may be needed before it is served on the nation's dinner tables.

If the FDA approves the sale of the salmon, it will be the first time the government allows such modified animals to be marketed for human consumption. The panel was convened by the agency to look at the science of the fish and make recommendations.

Ron Stotish, chief executive of the Massachusetts company that created the salmon, AquaBounty, said at a hearing Monday that his company's fish product is safe and environmentally sustainable.

FDA officials have largely agreed, saying that the salmon, which grows twice as fast as its conventional "sisters," is as safe to eat as the traditional variety. But they have not yet decided whether to approve the request.

Critics call the modified salmon a "frankenfish" that could cause allergies in humans and the eventual decimation of the wild salmon population. Representatives from consumer, environmental and food safety groups asked the agency to decline the company's application.

It is still unclear whether the public will have an appetite for the fish if it is approved. Genetic engineering is already widely used for crops, but the government until now has not considered allowing the consumption of modified animals. Although the potential benefits - and profits - are huge, many people have qualms about manipulating the genetic code of other living creatures.

Genetically engineered - or GE - animals are not clones, which the FDA has already said are safe to eat. Clones are copies of an animal. In GE animals, the DNA has been altered to produce a desirable characteristic.

In the case of the salmon, AquaBounty has added a growth hormone from a Chinook salmon that allows the fish to produce growth hormone all year long. The engineers were able to keep the hormone active by using another gene from an eel-like fish called an ocean pout that acts like an on switch for the hormone, according to the company. Conventional salmon produce the growth hormone only some of the time.

Critics have two main concerns: the safety of the food to humans and the salmon's effect on the environment. They worry that the fish will escape and intermingle with the wild salmon population, which is already endangered. They would grow fast and consume more food to the detriment of the conventional wild salmon, the critics fear.