(NaturalNews) The biggest seller of organic foods has decided to greatly reduce the number of antibiotic-treated salmon it purchases from Chile, a move that's expected to a deliver a huge financial blow to the aquaculture industry.

Costco recently announced that they will no longer be buying the majority of its salmon from Chile, the world's second largest producer of the fish, following an increase in consumer awareness regarding the dangers associated with the widespread use of antibiotics.

The extensive use of human drugs on farmed animals, including fish, is contributing to an increase in superbugs, or microorganisms that have grown resistant to antibiotics, posing a severe threat to humans, as these types of infectious diseases are more difficult to treat.

Costco drastically cuts farmed salmon purchases from Chile

Previously purchasing about 90 percent of its salmon from Chile, the membership-only warehouse says it will now buy just 40 percent from the South American exporter as they look to Norway (the world's largest salmon producer) to supply the majority of their demand.

Over the last few years, Wal-Mart, Wegmans and Safeway have also reduced purchases of Chilean salmon.

For eight years, Chile has been struggling to contain the spread of a virus that is killing millions of fish; in response to this and widespread bacterial disease, Chilean farmers have turned to antibiotics in order to keep their fish stock alive despite unsanitary conditions. In 2008, Chile used nearly 350 times more antibiotics on its farmed salmon than Norway, its chief competitor.

Industry officials say this is because Norway has developed vaccines to protect their salmon against illnesses, a development that Chile has been unable to achieve due to a lack of funding.

Under a new "information access law," Chile's government, for the first time, revealed information detailing its use of antibiotics in salmon production following a request by the environmental group Oceana.

While the high usage of drugs raised alarm, the industry defended its practices, claiming that the antibiotics are approved by the U.S. Food and Drug Administration (FDA) and is the only method available to fight fish-borne illnesses including rickettsia.

Several years ago, however, three Chilean salmon-farming companies were caught using a number of drugs not approved by the FDA, some of which include the antibiotic flumequine, oxolinic acid and the pesticide emamectin benzoate, according to Grist.org.

The illness plaguing millions of salmon, rickettsia, is caused by a parasitic bacteria known as SRS which is carried by sea lice that causes skin lesions and hemorrhaging in infected fish, resulting in the swelling of their kidneys and spleen, which eventually kills them. The disease was first reported in Chile in 1989.

Environmental groups blame unsanitary conditions and cramped pens as "super lice" infect marine life

The environmental group Food & Water Watch says^[PDF] ocean aquaculture, "the mass production of fish in large, floating net pens or cages in the sea — has often led to environmental and other disasters in the countries where it has been practiced commercially."

When farmed fish escape into wild, it's a major cause for concern as they pose an enormous threat to wild fish due to the diseases they carry.

Unsanitary and cramped living conditions allow disease to run rampant among farmed fish (similar to factory farms on land), making them more susceptible to pancreatic and amoebic gill disease, infectious salmon anemia (ISA) and an increase in sea lice, a destructive parasite commonly found in highly stocked net pens.

Sea lice has also become resistant to pesticides, allowing them to morph into "super lice," killing both captive and wild fish.

Despite assurances that farmed fish wouldn't survive in the wild, they've been identified in more than 80 rivers in British Columbia. More than 500,000 farmed fish escapes occurred in 2009, according to Norwegian farming statistics, including cod, halibut, salmon and trout.

It's also feared that farmed fish, which have minimal genetic diversity due to inbreeding, may mate with wild fish and over time cause them to lose "natural traits that help them survive in the wild."

Click here for more information on salmon aquaculture.

Sources:

News.Yahoo.com

NYTimes.com

Grist.org

FoodandWaterWatch.org^[PDF]

UnderCurrentNews.com

WHO.int

PBS.org