California fishery officials, mulling options for fighting the razor-toothed northern pike, are drafting plans to erect a mile-long barrier across a Sierra Nevada lake to trap the fish--and force it to eat its own young next spring.

Two years ago, state officials poisoned the lake in an effort to destroy the pike, but instead managed to kill almost all the fish in the lake and make the water undrinkable for months.

The barrier--either a net or a screen--is one of several strategies that state and local authorities have devised to purge Lake Davis of the nonnative northern pike, a fierce game fish experts fear could threaten California's salmon and trout populations if it slips into the state's river system.

Scores of pike have been found since spring in the mountain lake in Plumas County 220 miles northeast of San Francisco. One pike, a lean, muscular fish with daunting teeth, was 27 inches long.

The barrier "is one of 11 things that are in the category of 'do all these things now,' " said Portola City Manager Jim Murphy. "It would be nine-tenths of a mile long across the southern edge of the lake at Mosquito Slough," the pike's spawning grounds, he said.

The barrier is intended to block the pike from escaping into other parts of the lake and, when the spawning period arrives, force them to eat their young or starve.

A task force of residents, local politicians and state officials had hoped to have their pike-fighting plans in place by Dec. 1. Perhaps the most visible of those plans is the barrier, the subject of numerous meetings last week in Sacramento and Portola.

The seven-mile-long lake, once the principal source of drinking water for 4,000 area residents, regularly freezes during the winter.

Treating the lake with chemicals to kill the pike, introducing pike-specific diseases and draining the lake have been ruled out, Murphy said.

In October 1997, the state Fish and Game Department outraged local residents when it poisoned the lake to eliminate the pike. It also killed most of the other fish in the lake.

The water remained tainted for months, the region's tourism economy suffered and the state ultimately approved a $10 million settlement to cover scores of local claims.

State experts believe the pike, a popular fish in the Midwest, were first put into Lake Davis several years ago by anglers who prized their fighting qualities.