Invasion Could Hurt Native Fish Escape Of Atlantic Salmon From Fish Farm May Cause Problems

When Richard Stoll hooked an Atlantic salmon recently in the Olympic Peninsula’s Elwha River, he knew it was no freak of nature.

A biologist, Stoll figured the fish couldn’t possibly have strayed thousands of miles from its home waters on the East Coast. Raised to adulthood in confined fish farms around Puget Sound, Atlantic salmon sometimes escape and, for the past decade or so, have occasionally shown up like lost travelers on the lines of local anglers.

But when fishermen around him began to pull dozens of Atlantic salmon from the Elwha, it was clear that what Stoll first thought was an odd stray had become an invasion.

“There were more Atlantic salmon running up the Elwha this year than Pacific salmon,” said Stoll.

It turns out that 60,000 adult Atlantic salmon escaped from a submerged, Puget Sound fish farm near Anacortes, Wash., in July. The 8- to 12-pound fish have been migrating up area rivers this fall, creating what some people say is a harmless bonanza for sports anglers.

But to a number of scientists, the foreign fish are far from harmless. While none of the Atlantic salmon are believed to have reproduced in the wild, the fish may be crowding out native salmon - eating their food, and, at worst, spreading diseases, biologists say.

The East Coast fish, along with other animals and plants brought here from elsewhere, represent a type of “biological pollution,” a phenomenon which some scientists say is beginning to rival toxic waste, logging and development as one of the top global threats to the natural environment.

Introduced into waterways accidentally or by design, foreign species have the potential to devastate aquatic ecosystems more thoroughly than conventional, industrial pollution, the scientists say. The creatures are permanently altering everything from beaches to shellfish beds to salmon runs.

In Washington state, they include an oyster-killing snail imported from Japan, a carp from China that can eat 100 pounds of aquatic plants a day, and is now degrading marshes in the Columbia River, a saltwater grass from the East Coast that is clogging beaches and mud flats in Willapa Bay on the coast, and an aquarium plant called hydrilla, which has made some area lakes virtually impassable to boats.

Last week, state fisheries biologists announced they have discovered for the first time in an Eastern Washington stream a European parasite that causes “whirling disease,” a syndrome in which young trout sustain nerve damage and then chase their tails until they die. The parasite has essentially obliterated the trout population in some Montana streams.

“It’s a little like the movie Jurassic Park,” said Hiram Li, a professor of fisheries science at Oregon State University. “You bring in species that don’t belong, and sometimes things can go wrong - terribly wrong.”

Compared with other parts of the world, the Northwest is relatively unblemished by dominant plants and animals introduced here from other places, biologists say.

But two of the most destructive are thought to be on the way.

One, the Green crab from Asia, is so proficient at cracking open clams and oysters that its introduction into San Francisco Bay has obliterated many shellfish beds there. Marine biologists have reported finding the crab in bays in Oregon recently, said John Armstrong, a senior scientist with the Environmental Protection Agency in Seattle.

“The Green crab is moving north, and if it comes to Puget Sound, it potentially could destroy the oyster industry,” Armstrong said.

The other is a tiny, bean-sized mollusk of no commercial value that is now being called the most dreaded animal species in North America.

Imported from Russia to the Great Lakes in 1986 when it hitchhiked in the ballast water of a ship, the zebra mussel has in 10 years reproduced by the trillions, draining lakes of nutrients and clogging water intakes.