for the New York Times editorial page
In 2007, a virus called infectious salmon anemia started killing millions of farm-raised salmon in Chile and devastated Chilean aquaculture. The virus was first detected in 1984 — long before salmon farming had spread around the globe — but what made it so lethal in 2007 was overcrowding in the offshore salmon pens and the fact that salmon were being raised in the midst of their own pollution. No one knew how the virus was transmitted, but a 2008 study at the University of Bergen determined it was carried in salmon eggs exported from Norway to Chile.
Salmon farming is a problem everywhere, but as it exists now in Chile — the second-largest producer, after Norway — it is simply unsustainable. Chilean aquaculture has made some reforms since 2007 — trying to reduce overcrowding, for instance — but a nonlethal form of the virus is still present.
What makes Chile different isn’t just the scale of its aquaculture. Its basic means of forestalling the salmon virus is tragic in itself: salmon-farming companies move their pens from polluted water to pristine water, edging their way steadily south down the fjords that define the Chilean coast. This is the equivalent of moving industrial hog farms onto virgin prairie. Much of the land around the fjords is protected as national parks and national preserves, but none of the waters are.
Salmon farming everywhere has repeated too many of the mistakes of industrial farming — including the shrinking of genetic diversity, a disregard for conservation, and the global spread of intensive farming methods before their consequences are completely understood. The death of millions of farmed salmon in Chilean waters was a warning sign that must be heeded.