Fish invaders ravaging Oregon lake

BURNS, Ore. – U.S. Fish and Wildlife biologist Linda Beck stood in water halfway to her knees, gazing out on a lake strangely empty of waterfowl.

Cormorants, pelicans, gulls and terns by the millions once wheeled and shrieked above Malheur Lake while ducks bobbed and dove for insects. Now, the lake and sky are eerily empty.

“I mean, there are no birds,” she said. “We still should be seeing some birds.”

There’s a one-word explanation for the dramatic downturn in waterfowl on the shallow, 50,000-acre lake: carp.

Their ranks have exploded over the course of decades – and nothing, not even a succession of wholesale poisonings, has beaten them back for long.

Carp out-compete the waterfowl for sago pondweed, aquatic invertebrates, insects and other food. They also root on the lake bottom, stirring up sediment and diminishing the sunlight necessary for the growth of lake grasses.

“It’s a giant carp pond,” said Audubon Society of Portland spokesman Bob Sallinger. “That lake is basically a dead lake.”

Migratory waterfowl, shore birds and colonial waterbirds used to darken the sky above Malheur Lake and the 187,000-acre refuge during their annual stop on the Pacific flyway. Duck production alone averaged more than 101,000 annually with a peak of 139,000 in 1946.

No more. Waterfowl production is down 75 percent at the refuge and visiting bird numbers have fallen by several million a year, according to the Fish and Wildlife Service.

Carp are native to Europe and Asia and were artificially introduced into the Silvies River in about 1920, probably to keep nearby irrigation canals open on the premise that carp would eat aquatic plants and algae, Beck said.

Their numbers in Malheur Lake – which averages 18 inches deep – verge on the unbelievable. Biologists estimate 1.5 million carp inhabit the lake.

On windless summer days, Beck said she sometimes stands on the deck of one of the refuge’s two airboats watching the dorsal fins of thousands of carp stir the water in circles an inch or two above the surface.

They remind her of the great white shark in “Jaws.”

“You just kind of look out across the lake and you see the fins,” she said. “It’s crazy.”