Genetically modified salmon is composed of DNA of different fish including eel. There are debates going on whether it could start new allergies and cause cancer. No long term studies pertaining to these questions exist. There's a possibility that if the fish escapes in to the ocean, it could cause havoc in our environment and since it grows so fast, deplete the food of the fish in nature that were not tapered with by scientists.
The GMO salmon does not have to be labeled as GMO food. Any Atlantic salmon you buy in the future could be genetically modified.
Enjoy your Frankenfish at your favorite Sushi restaurant and at your dinnertable...