Arctic Science Journeys
Radio Script
1997

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Farm Fish Break-Out
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STORY: Salmon farming is a rapidly growing business in the chilly coastal waters of the northern U.S., Canada and Europe. But salmon sometimes escape from their pens, and that has scientists worried about the future of wild salmon stocks.

Mary Colligan is a biologist for the National Marine Fisheries Service. She's studying what happens when Atlantic salmon escape and breed with their wild counterparts in Maine.

COLLIGAN: "The aquaculture, commercial culture growers are interested in different characteristics. They're interested in fast growth, in healthy fish, in fish that perform well under a controlled aquaculture setting, and those characteristics are likely not the same as a fish that would perform well in the wild."

Protecting wild salmon is important because the fish have adapted to their environment over thousands of years. Cross-breeding domesticated salmon with wild salmon could weaken the wild salmon's ability to survive the rigors of nature.

Each summer, millions of wild Pacific salmon return to spawn in rivers and lakes of Alaska and British Columbia. At the same time, farmers raise Atlantic salmon in pens along the coast. Scientists like Bill Smoker from the University of Alaska Fairbanks aren't so much worried that farmed salmon will breed with wild salmon. Genetically, Atlantic salmon are different from Pacific salmon, and successful breeding between the two would be difficult. More worrisome, says Smoker, is the prospect that farmed salmon will escape and find the wild to their liking.

SMOKER: "That's not to say that there isn't also a risk of Atlantic salmon escaping from farms in British Columbia and becoming established in coastal waters or freshwater habitats and therefore competing with and driving out wild populations. That's another risk."

Salmon have escaped from farms in British Columbia and Washington. Some 64 thousand farmed Atlantic salmon escaped from British Columbia pens in 1994, according to the B.C. Salmon Farmers Association. But so far there's no evidence they've established themselves in the wild. Norway, however, hasn't been so lucky. Bill Smoker.

SMOKER: "There's strong evidence that in Norway escaped Atlantic salmon from farms have predominated in many wild spawning populations, probably to the detriment of those populations."

The situation bares careful watching, according to Colligan. She says that this year scientists in Maine did find sexually mature salmon from fish farms heading up rivers to spawn.

OUTRO: For Arctic Science Journeys, this is Robert Hannon reporting from Fairbanks, Alaska.