If this were a B-grade science fiction film, the credits would be rolling about now. The invaders would be dead, the good guys proven triumphant.
Unfortunately, the predatory northern pike don't know when to quit at Lake Davis.
So far, the voracious and fast-spawning fish have been hit with explosives. They've been choked with chemicals and stunned with electric shock. They've been scooped up in nets and herded into narrow sloughs.
Over the lazy days of summer, the saw-toothed invaders dodged innumerable fishing hooks -- just 12 were pulled in by anglers last year.
The pike has become a first-rate nightmare for the state Fish and Game Department -- and a gut punch for Portola, a tiny north Sierra tourist town an hour's drive from Lake Tahoe.
In 2000, about 600 pike were caught during eradication efforts. The number jumped to more than 6,000 in 2001. Last year, it catapulted to 17,635, though fewer than 200 were deemed mature adults capable of ambushing the lake's trophy salmon.
Uncontrolled, the carnivorous fish loom as a monumental threat if just a few escape to the Sacramento-San Joaquin Delta and began multiplying and ravaging its fisheries.
This year's projected growth curve looks grim. Calculating conservatively, biologists say the pike population could grow to 47,000 by this spring. Worst case is 94,000. "The odds of holding our own doing what we're doing now are very slim," lamented Ivan Paulsen, a Fish and Game senior biologist.
Such stark conclusions have a few locals talking about pulling out big guns. Most suggest it is time to consider poisoning the pike once again. The state's 1997 attempt at chemical treatment spawned lawsuits and a monumental public relations fiasco, but failed to stamp out the fish.
Once a drinking water source for Portola, the lake was rendered off-limits. State health officials eventually deemed it safe, but the community is waiting for improvements to its water treatment plant before looking again to the lake for water. To settle the litigation, the state paid residents $9.2 million in reparations.
But some residents say it is becoming obvious that the current methods are putting only a dent in the growth curve of the pike, which typically don't range beyond the Midwest, but somehow were planted in Lake Davis. They suggest that chemical treatment, perhaps combined with draining the lake to herd the fish into a small area, will be needed to eliminate the pike.
"We have two choices now," said Tony Olson, who owns a motel and four cabins at the lake's edge. "We either let the pike take over the lake. Or we treat the lake. There's no way around it."
The Lake Davis Steering Committee -- a collection of local and state officials -- is expected to begin tackling such thorny topics when it meets Tuesday. Not everyone buys into poison as the silver bullet. For some, the memories of 1997 are too fresh, too bitter.
Committee Chairwoman Fran Roudebush said it's too soon. Poisoning poses environmental and health risks, and draining the lake could take half a decade, hurting the economy even more.
She hopes the current push to contain and control the fish will curb the population at an acceptable level. The media, Roudebush said, haven't done the community any favors, writing articles and airing news stories that highlight the big numbers but ignore what she said is a rosier reality.
Of the nearly 18,000 fish caught last year, only 198 were of sufficient size -- 18 inches or more -- to tackle the lake's trout. (A pike typically has to have about twice the body length of the fish it attempts to eat; most of the trout planted in Lake Davis -- more than 50,000 last year alone -- are 9 inches or longer.)
"The pike have not taken over this lake," Roudebush said. "We're holding our own. But the media is killing us on this. Just killing us. Our trout fishery is alive and well, and people should come back to Lake Davis."
Such pleas didn't pay off last summer. Rentals were down about 50%, and other businesses that depend on Lake Davis tourist traffic experienced a similar slide, Roudebush said.
She believes spring could bring a measure of hope. Last year, biologists tested a type of explosive known as detonation cord. A shock wave produced by the explosive -- wound across about an acre of the lake's surface -- proved effective at killing nearby fish.
After the ice melts this spring and before the tourist season goes into full swing, Fish and Game officials plan to set off detonation cord on as much as 10 acres at a time.
Wildlife experts aren't optimistic that tactic will turn this war. Paulsen of the state Fish and Game Department estimates that, at best, current tactics will simply double the number of years it takes the pike to saturate Lake Davis.
"It's kind of like hunting an elephant with a .22," he said. "If you get lucky, you can kill it. But the odds are not good."
Paulsen said better public education could overcome a repetition of 1997's problems with the poison, which is approved by the U.S. Environmental Protection Agency and is the active ingredient in a can of bug spray.
But doubters such as Roudebush say they'll need proof the chemical can't leach into wells that supply shoreline cabins with drinking water.
Another possibility might be what Paulsen dubs the sugar and spice plan. Though untested, it would involve dumping molasses and corn syrup into the lake. The mixture feeds bacteria that deplete oxygen in the lake, killing fish.
But the pike have proved resilient. In 1997, some locals believe, a few of the fish avoided the chemical plume by swimming deep enough to benefit from fresh springs that feed the lake. Once the poison dissipated, they were back in action.