One of the most significant environmental concerns about genetically engineered salmon is that if they were introduced into the wild salmon population, they would cause its extinction. This is a theoretical scenario discovered earlier by Muir, which he termed the Trojan gene effect. However, Muir examined fitness data and concluded that AA salmon are less fit than their native counterparts, meaning that natural selection would simply purge them from the wild population.

"The Trojan gene effect does not apply in this case, and there is no evidence to support concern for an extinction event," Muir said.

Muir also points out that AquaBounty has developed multiple redundant safeguards to prevent the fish from entering natural populations.

First, only triploid eggs – which have three copies of each chromosome - would be sent to Panama from Canada. That means 99.7 percent of the fish are sterile. All the fish would also be female, unable to breed with each other.

Second, the facility in Panama is land-based, with screens to keep the salmon inside. Panama was chosen as the farming site because its waters are tropical. If fertile AA salmon were able to escape the holding barriers, they would perish when reaching water too warm for their survival.

Finally, in the unlikely event that fertile fish escaped and survived in the surrounding oceans, they would have to swim several thousand miles to find possible spawning streams and mates.

Regarding human health concerns, AA salmon were said to have more allergens than non-genetically engineered salmon. This raised concerns that consuming the genetically engineered versions could harm people.

But the data did not support this assertion. Muir said there is no baseline for the amount of allergens a fish may contain before it is unsafe for consumption and that many fish consumed regularly, such as herring, have significantly more allergens than AA salmon.

"There is as much as a hundredfold difference in the allergenicity among fish," Muir said. "At what level should it trigger concern?"

Muir also argues that the FDA will treat AA salmon like a new drug that has been through the regulatory process. The agency can approve and continue to monitor the salmon. If new concerns are raised and found to be valid, the government could withdraw its approval.