The FDA announced that it has given the go-ahead to an application from AquaBounty Technologies for genetically engineered Atlantic salmon, which grows twice as fast as its conventional farmed counterpart.

In its release, the FDA said that the salmon is as safe and nutritious as non-genetically engineered salmon and that “there are no biologically relevant differences in the nutritional profile.”

The FDA is prohibiting the genetically engineered salmon, called AquAdvantage Salmon, from being raised in the U.S.—instead they will be grown in tanks in Canada and Panama. The FDA also said the fish are also sterile so they will not be able to breed with conventional salmon if they break free of their tanks.

Under FDA guidelines, the AquAdvantage Salmon will not require a GMO label.

The seal of approval from the FDA may not be enough to convince some major retailers to carry the fish. Environmental group Friends of the Earth says about 60 major retailers, accounting for more than 9,000 stores, have non-GMO seafood policies. That includes big names like Whole Foods (WFM), Trader Joe’s, Sprouts (SFM), Safeway (SWY), Target (TGT), and Kroger (KR). Absent from that list are Walmart (WMT) and Costco (COST).

But retailers’ hesitancy to carry the genetically modified seafood should not be taken as a judgment call on whether they believe the AquAdvantage Salmon is safe. It’s more of a response to consumers’ wariness. When the FDA opened up the issue of genetically engineered Atlantic salmon to public comment in 2012, it received more than 38,000 comments online. Of the 1,207 made public, most were negative.

And it’s not just seafood. Consumers have concerns about GMO food more broadly. A 2014 Pew Research Poll found that 57% of U.S. adults believe that genetically modified foods are “generally unsafe” to eat.