Pike’s Resurgence Has State Fishing for a New Strategy

It was a good season for northern pike in Lake Davis. That is bad news--for California taxpayers, for rainbow trout and for anglers.

Four years after the state conducted a controversial $14-million program to rid the Plumas County mountain reservoir of the pesky nonnative, the pike population is rapidly expanding.

About 5,000 pike were caught by state Fish and Game Department workers this year, about eight times the number snared the previous year.

“They had a good spawn,” said senior Fish and Game biologist Ivan Paulsen.

There are not nearly as many pike as there were before the state poisoned the man-made lake in 1997, Paulsen said. But there are enough to start hurting Davis’ other fish species and to send the state searching for new answers to the pike problem.

Pike are big, fecund and hungry, native to the eastern United States. No one knows exactly how they first got into Lake Davis, a prime trout fishery in the Plumas National Forest northwest of Reno. Nor are biologists certain how they managed to reappear after more than 50,000 pounds of the chemical rotenone were poured into the lake, killing most of its animal life.

Genetic testing indicates that the pre- and post-poison pike are related, suggesting two possibilities: Some pike may have survived the chemicals--by hiding in springs or tributary pools--or someone saved some pike and then dumped them back into the lake.

Since then they have been busy reproducing, something pike are quite good at. For each pound a female weighs, she can deposit up to 9,000 eggs. The biggest female caught this year was capable of producing 80,000 eggs.

State Fish and Game has stationed four full-time staffers, including Paulsen, at the lake along with a number of seasonal workers. With some help from private contractors, they are using gill nets, purse seines and electrofishing to catch as many pike as they can in the 4,500-acre lake.

DNA Tests Seek Intruders’ Origin

The electrofishing, done off a flat-bottom boat or with backpack equipment, sends an electrical pulse into the water, stunning the fish, which are then collected. The pike are killed and other species caught are returned to the lake.

Pike from the lake have been sent to the state’s wildlife forensics laboratory for DNA testing. In addition to ascertaining whether the pre- and post-poison pike are related, scientists are trying to determine where the pike originally came from. So far, Paulsen said, they have not been able to link the Davis strain to other populations.

The catch and monitoring program is costing more than $500,000 a year, and it will not eliminate the pike, just control them.

“This program is designed to buy some time,” Paulsen said.

The chemical poisoning was expensive and unpopular, making a repeat unlikely. It temporarily knocked out the trout population on which the local economy is largely dependent and forced the nearby town of Portola, which used the lake for drinking water, to drill wells instead. Part of the cost of the program was $9 million in reparations to local businesses, the county and the city.

The state is now considering the use of detonation cords. They would be exploded in parts of the lake with high pike concentrations, creating shock waves that would kill any fish in the vicinity. The environmental impact of the detonations--including whether they would create toxic residues--is under study.

Another option, currently at the bottom of the list, is to drain the lake. That would destroy the trout population for at least two years, delivering a huge blow to the local economy.

“We have a problem, and tough decisions are going to have to be made,” said Jerry Dollard, who runs a local convenience store and sits on the steering committee of the Lake Davis Task Force.

Portola Councilman John Larrieu, who is also on the committee, said townspeople don’t know what the solution is.

“They sort of feel a sense of futility,” he said. “There’s not a lot they can do.”

But the stakes are too high for the state to let the pike triumph. If the population explodes again, the pike will eat all the Davis trout, and eventually, Paulsen said, spread beyond the lake. That could be catastrophic, since the reservoir system is connected to the Sacramento-San Joaquin estuary, part of a highly valuable commercial salmon fishery.

“I don’t think we’re willing to throw in the towel and say, ‘No, we can’t do this,’ ” said Fran Roudebush, chairwoman of the Save Lake Davis Coalition and a former county supervisor. “Our ultimate goal is to eliminate the pike and keep them from California.”