Issues to discuss

In Portugal salmon is maybe the 3rd species among seafood most consumed.

It is imported, most of it from Norway, where it comes 80% of salmon imported in EU.

Moreover imports from China are on the increase, but this is actually Norwegian salmon which has been filleted and frozen in China. 
The two major EU importers of Norwegian salmon are Sweden and Denmark, although they only act as hubs and actually re-export almost everything to the main EU markets for salmon (France, the United Kingdom, Germany and Poland). 
This specific role of Sweden and Denmark explains why the value of intra-EU trade seems to be as big as the value of imports.

Some ethical and environmental issues are important to discuss, here and there in the USA, where the GMO salmon production for food can be approved one day:

GMO salmon—or franken-fish, as it is sometimes called—is an Atlantic salmon whose DNA has been re-engineered with a “growth-hormone gene construct” made from genetic material of other fish. 
One of these fish, the ocean pout, is only as closely related to Atlantic salmon, taxonomically speaking, as a human is related to a porcupine or a platypus. 
This recombination of genetic material would never happen in nature. 
 Beyond being designed and engineered by humans and created in a laboratory, GMO salmon and Frankenstein’s monster may also share another defining feature—larger-than-normal proportions. 
AquaBounty Technologies, the company behind GMO salmon, has always insisted that its fish grow muchfaster than normal Atlantic salmon—but not larger. 
This is one of the most frequent claims the company makes—to journalists and even to financial regulators at the Securities Exchange Commission. 
 But, according to a recently released scientific review from the Canadian government, AquaBounty doesn’t have a shred of evidence supporting this claim. 
This is more than a little odd because AquaBounty calls GMO salmon the “most studied fish in the world.” 
If it turns out that GMO salmon do grow larger than normal salmon, it would almost certainly provoke even further consumer opposition to the fish while also compromising the company’s pending risk assessment with the FDA. 
As Canadian government scientists note, a larger-than-normal Atlantic salmon would be able to eat larger-than-normal prey fish, and this expanded diet could expand the environmental impact of escaped GMO salmon. 
Other important risk-assessment questions also emerge: 
What happens to the health of a GMO salmon that reaches ever-large proportions? 
What happens to the nutritional content of the fish for consumers? 
What happens to the hormone levels of this fish, which is engineered with a growth-hormone gene construct?