There are legitimate concerns surrounding genetically modified foods. Some potential problems include the creation of monocultures that permit rapid and more complete devastation from disease, selective pressure that creates superior pests and predators (positive feedback toward creating monocultures), negative ecological network effects, overuse of pesticides, and reliance on commercial seed (you think software patents cause problems...). Food safety is one, but it's a given for crops intended for human consumption.

That said, the real problem is fear from people who do not understand the science. We've been modifying what we eat for thousands of years. Selective breeding has allowed us to feed today's world. Development of short-stalk, high-yield, disease resistant wheat by Norman Borlaug in the 1950s secured a food supply for Mexico and India. His cultivars are now credited with saving more than a billion lives. Where selective breeding got us to where we are today, genetic engineering will carry us into the future. We need higher yields per acre to support a growing population. That means industrialized farming and cultivars that support industrial methods. So-called "Roundup-ready" varieties of plants allow mass spraying of herbicides over fields, and let desirable plants crow without competition from weeds (the plants have been made resistant to the herbicide). Corn engineered to carry the "Bt" gene for a bacterial endotoxin produces its own insecticide. In each case the modification allows for a higher yield per acre. Some may say that selective breeding is different than recombinant methods, which is true. Introducing exogenous DNA into an organism is different than crossing two parent organisms. The introduction of new DNA or new alleles does occur in nature however, via viral insertion or mutation. Somewhere between 5% and 10% of our own DNA is the result of viral insertions. Plants and salmon are effected by viruses too. We are only accelerating evolution down particular paths (albeit perhaps down very unlikely paths).

So genetic modification is not inherently harmful, and it can confer wonderfully advantageous benefits. Baseless fear is unwarranted, but cautious concern is justified. When having debates or reporting on GM foods it is important that we discuss both the benefits of GMO foods along with the concerns I mentioned above. It is prudent that any new organism be fully studied and understood before it is deployed in the outside world, and at a large scale. Environmental impact needs to be understood. In the US, GMO foods must clear many regulatory hurdles before being approved. Among these are complete characterization of the genomically integrated transgene(s) and demonstration that the transgene(s) remains stable over multiple generations. Apparently these and other criteria have been met to the satisfaction of the reviewers examining the farmed salmon. Here is the environmental impact study provided to the FDA by the salmon company:

http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMe...

Even though I support genetic engineering of foods, I am against labeling of GMO foods as currently proposed because I think a simple statement is inadequate. Saying "GMO food" says nothing about the modification, and only serves to incite fear. In a time of rapid whole genome sequencing, I want to be able to scan a QR code on a package and get a link to the GenBank entry for the food organism in question, along with the impact studies and a plainly worded overview. I want to see notes for which insertions, deletions, or other changes were made. I want to see the DNA diff on the genomic source code. Public food should be open source.

A few years ago I had lunch with Richard Stallman (a fun story itself), and wanted to get his take on gene patents and "closed source" organisms. While he expressed an understandable disapproval of corporate monopolies on crops and biopharmaceuticals, he did not seem to have a strong desire for Freedom in genetically engineered products. I found that surprising. He thought the barrier to entry was too high for people to make their own genetic changes as they might make changes to software. I think we need to consider that genetic engineering is only going to get easier.

From some cursory reading it looks like the salmon in question in this article has been modified with a promoter (kind of like a compiler flag to enable production of a gene product) from the pout fish, and a subsequent growth hormone gene from a different salmon species. It grows faster, is more aggressive, and is sterile. It seems that the aquaculture companies interested in using the fish intend to keep it isolated from the outside environment, but even in the event of a release the fish would merely eat prey. They would ultimately die. Since they are sterile, the likelihood is low that they would be able to outcompete unmodified variants in their single generation. It seems they are safe all around.

If anyone is curious, the inserted gene construct is known as opAFP-GHc2, and its CDS source is available:

http://www.ncbi.nlm.nih.gov/nuccore/56691717