Salmon farms pose significant threat to salmon fisheries in the Pacific Northwest, resear...( ket share not only to overseas competit...)

ket share not only to overseas competitors but also to local farming operations. Salmon aquaculture was virtually nonexistent in the Pacific Northwest prior to 1985. But today, 70 percent of the salmon produced in British Columbia and Washington comes from salmon farms - 121 in British Columbia and nine in Washington.

Ecological threats

Salmon aquaculture is currently prohibited in Alaska, for economic and environmental reasons. Raised in pens built along the shore, farm salmon are particularly susceptible to diseases and parasites, such as sea lice, that can be lethal to fish. The report cited instances where lice, viruses and other pathogens have contaminated wild salmon stocks swimming nearby.

"A more insidious ecological risk to wild salmon comes from the escape of farm fish from netpen facilities," the authors wrote, noting that well over a million salmon have escaped from farms in Washington and British Columbia during the past decade. Most of the escapees were Atlantic salmon (Salmo salar), which, although not indigenous to the Pacific Northwest, are the main species raised in West Coast fish farms.

"Escapees are capable of establishing and reproducing in the wild and competing with wild salmon populations for food and habitat," according to the authors, who noted that Atlantic salmon have been found in dozens of rivers and lakes throughout British Columbia and Alaska. The report also found that open netpen aquaculture can threaten other organisms by releasing untreated nutrients, chemicals and pharmaceuticals into the marine ecosystem. Such concerns led the government of British Columbia to establish a six-year moratorium on salmon farming in 1996. Strict regulations for waste disposal were finally introduced last year when the moratorium was lifted. Whether the regulations are successful in curbing pollution will depend on how rigorously they are enforced, the authors wrote.

Year-round demand
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Contact: Mark Shwartz
mshwartz@stanford.edu
650-723-9296
Stanford University
22-Sep-2003

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