Fish Farming and the Extinction of Salmon

Farmed fish arrive in open water with an advantage. Their rapid growth floods them with hormones that make them more aggressive. By interbreeding with native salmon, the escapees dilute time-tested genes that let wild fish flourish. The result: inept hybrids less likely to survive.

It tips them toward what biologists call an "extinction vortex."

"You'd expect the entire stock to eventually fail as a result of failing fitness," says Dagfinn Gausen, an adviser at Norway's Directorate of Nature Management. "There's no way to get rid of it as long as you have a constant flow of more and more farmed fish."

Doing things smarter Haavard Grontvedt grew up feeding frozen chunks of fish to salmon on his Uncle Sivert's pioneering farms at Hitra. Now he is regional director of Marine Harvest, the largest salmon farming company in the world. Marine Harvest owns what was Sivert Grontvedt's first farm, visible from the home where he lived until his death in February.

The clanking complex of steel catwalks and automatic feeders is a far cry from the round wood pens the father of salmon farming pioneered.

Haavard is tall, and he is frank. He smokes Marlboros as he steers his Audi through Hitra's fishing villages. The drive to keep prices low pushes farmers to cut costs, he says. Their challenge is not to sacrifice environmental protection for that same goal.

Like any evolving business, salmon farmers are learning to manage their operations more wisely, he says.

"There's a lot less cowboys in the industry than there was," he says. "We are smarter in the way we do things, and that's good for us and the environment."

More than two-thirds of Marine Harvest's farms in central Norway rotate nets in a way that limits escapes while reducing the need for chemical net protectants. The company also treats its salmon for lice more aggressively, a new government requirement.

At first it seemed bothersome, he says. But it kept lice numbers low enough that fewer treatments are needed overall. Federal biologists credit Norway's farmers with vast improvements.

"The cost of treatment is much lower than it was some years ago, and that's what we want," Haavard Grontvedt says.

Waste from farms has not proved a conspicuous problem. Farm sites are placed only where currents wash detritus away and are commonly left dormant for several months between crops of fish. Companies must survey the seafloor beneath the pens.

Farmers have reduced the fraction of fish that escape to less than one-half of 1 percent and have cut back lice. Still, Norway's farmed salmon numbers keep rising.

"The problem is the production is so enormous that even if the proportion is small, the number of fish is enormous," says Torbjorn Forseth, research coordinator at the Norwegian Institute for Nature Research. "The more fish, the more lice, the more disease."

Industry fought a plan that aimed to protect fjords vital to wild salmon by ousting farms. So most farms can stay put. The government adopted tighter controls for escapes, but they will not take full effect until 2008. Fish managers would like to plant tiny ID tags in farmed fish at a cost of about a nickel each so farmers could be penalized when their fish get out.

But the industry rejects the idea as too expensive.

"They keep telling us they are doing better," says Aage Wold, looking down on the Maana from an old wooden bridge. "But then they never do."

Although escapees have overrun the Maana, he says none of the nearby farms reported any escapes -- as the law requires.

Salmon farms plow little income into local towns, he says. Profits go to distant corporations and stockholders in Oslo or the Netherlands.

The costs are all too clear for the river he once fished with poles crafted from tree branches.

"We caught many more small salmon at that time than we do now," Wold says. "We wonder, 'Where have they gone?'"

Michael Milstein
michaelmilstein@news.oregonian.com 

The article first appeared in "The Oregonian" on November 30th 2003.