Free Four Fish by Paul Greenberg

(like the world’s second-largest salmon producer, Chile, for example), salmon are considerably cleaner. That is simply because, overall, there is far less industry in the Southern Hemisphere than in the Northern; therefore Southern Hemisphere feed pellets are correspondingly lower in industrial pollutants.
    But the subtlety of this information did not make it into the press. Like all information on food safety, it reached the public in binary fashion—wild salmon are good and farmed salmon are bad. And there was an immediate drop across the board in farmed-salmon consumption. Perceptual improvisations also occurred in a kind of toxicological game of telephone. Armchair environmentalists have often pointed out to me that farmed salmon have high levels of mercury. In fact, mercury contamination in farmed salmon is not a particularly salient issue. No significant difference in mercury levels has been found between farmed and wild salmon, and neither farmed nor wild salmon have dangerously high levels of that contaminant.
    The Hites and Carpenter study also spurred counterattacks from the salmon-farming industry, which claimed that there were important benefits from eating oily fish like farmed salmon that outweighed risks from PCBs. “Long” fatty-acid chains found in salmon, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)—often referred to collectively as the omega-3 fatty acids—are used by fish to keep their cell membranes pliable in cold-water environments like coastal Greenland and Alaska. When eaten by humans, these amino acids have the same effect on human vascular tissue—keeping veins and arteries fitter and more youthful longer. The salmon industry argued vehemently that this effect was not being taken into consideration by the Pew-funded study. This position was amplified when the National Institutes of Health funded a study by the Harvard Medical School’s Dr. Dariush Mozaffarian. The Mozaffarian study compared the risks of cancer death from PCB poisoning related to farmed-salmon consumption with the risks of coronary heart disease death from not eating farmed salmon. When I spoke to Mozaffarian this past year, he told me he felt that comparing the PCB cancer risks of eating farmed salmon with the coronary risks of not eating oily fish like farmed salmon was like “comparing sesame seeds with watermelons.” Mozaffarian’s meta-analysis found that 23 cancer deaths per hundred thousand individuals were likely to occur if people ate three portions of farmed salmon per week. If the same hundred thousand people did not eat farmed salmon or other oily fish, 7,125 deaths from coronary heart disease were likely to occur. Carpenter and others have subsequently countered that they believe Mozaffarian’s selection from the scientific literature for his meta-analysis was not representative of the larger trends and failed to take into account preliminary evidence that PCB contamination in farmed salmon may offset the coronary benefits of omega-3 fatty acids that an eater of farmed salmon would likely obtain.
    Mozaffarian says he would and does feed farmed salmon to his two-year-old child. Carpenter maintains that farmed salmon is “dangerous food.”
    There is, however, one point on which Mozaffarian and Carpenter agree. A single 1.8-gram pill of omega-3 oil supplements, available in forms that are guaranteed PCB-free and harvested from sustainable sources, provides as much coronary benefit as eating salmon, farmed or wild.
     
     
     
    T he lower-forty-eighters and Europeans who eat the bulk of the world’s farmed and wild salmon are endlessly obsessed with prolonging life and avoiding long-term health risks. But the native people who catch wild salmon today, like the Yupik nation of the Yukon Delta, seem to have an increasingly tenuous hold on existence. A bad turn of fate can be all it takes to make a tribal member voluntarily leave this troubled world, particularly if that tribal member is a