All Atlantic Salmon* is farmed, so for it to be "Norwegian" it had to come from a farm off the coast of Norway (which is the world's third largest source) then shipped to Greece for further processing. The colour is added in their feed because they're pale compared to wild salmon otherwise; so Greece was potentially where it was filleted & cured. The trip to Greece would have probably been by ship, whole, frozen. Possibly on ice, by truck, but Greece is a long way from Norway by road.
It could even have been processed before shipping or en route, so Greece was left to do just the final packaging.
Some details & numbers on this page - 5 Key Differences Between Atlantic Salmon And Wild Salmon.
Shipping information from SeafoodFromNorway.com
*Atlantic Salmon is the species, there's only one in the Atlantic, whether it's called Canadian, Scottish or Norwegian.