hmmm, i am not sure i understand how the pigment levels can determine the origin of the fish, heres why:
in farms, salmon are fed feed with either astaxanthan or canthaxanthan added to it. this serves the purpose of coloring the flesh, although the salmon do not do well without it in their diet. the chemicals used are
nature-identical, although they are produced in a lab. Both wild and farmed are colored by the same chemical, but it needs to be supplemented in captivity because the fish meal that the salmon eat does not contain high enough levels. an interesting aside, astaxanthin and canthaxanthin are very powerful antioxidents and are VERY good for you. you can find them available in tablet form at many health food stores. here's proof
http://www.lifesvigor.com/prod/16851/
the same two nature-identical additives are used to keep egg yolks yellow, and are supplemented to chickens as a matter of course. the poulty industry gets to dodge the bullet because they have a large political lobby, but the fish industry is disjointed and uncoordinated.
anyway, i would still be wary of testing pigment levels, since both wild and farmed salmon contain naturally varying amounts of pigment. King salmon in particular are found with flesh that ranges in color from paper-white to nearly fire hydrant red. this is a natural variation based upon the fishes diet. sockeye salmon (a wild fish) contain extremely high levels of pigment, one reason why it is so good for you. coho, pink, or chum salmon have very low levels, which is why they lack the characteristic red color of the other two wild salmons.
the article states that ONE
anonymous expert considers the tests to be "a method that is accepted," but it strikes me as odd that you can tell the difference between the same chemical in a fishes' flesh regardless of origin.. is it possible to tell the difference between vitamin A from a carrot and vitamin A from a pill, if it is the exact same form of vitamin A and it has already been absorbed and placed? perhaps, but it doesnt sit well with me.
also the NYT is the same paper who posted the EWG/PEW study of farm raised salmon, which seemed to indicate that farmed fish had higher levels of PCB contamination than wild fish...a study that has been replicated several times and has NEVER come back with the same results...in fact, every time it is replicated the farmed fish comes back cleaner than the wild fish...PEW/EWG has had it out for farmed fish ever since the industry survived their legal onslaught in the mid nineties, and are notorious for cooking results.
based on my experience i would be very surprised if there is any way to tell the difference without a genetic profile...even then, knowing that most salmon start their lives on farms (hatcheries), i would not be surprised if most "wild" fish test as farmed.
Erik.