A decade after the state first tried to eradicate the voracious northern pike from pristine Lake Davis in Plumas County, Department of Fish and Game (DFG) employees are back–same fish, same chemicals but with a less hostile local populace and new satellite technology.
More than 500 DFG personnel–scientists, field workers, water experts and others–are in Portola staffing the three-week-long eradication effort that will start with treating the lake’s streams and tributaries and culminate with the treatment of the lake itself.
“For this project, DFG took extensive steps identifying all possible pike-bearing waters up to 4 _ miles from the reservoir, using satellite technology and other intensive survey methods. Because treating the tributaries and streams is critical to eradicating pike, DFG officials will be on site to describe the current treatment, as well as to discuss the entire eradication project,” the department said.
Fish and Game experts say the pike, a popular Midwest fighting fish, would devastate California’s trout population if allowed to get into the river system. Authorities aren’t sure how the pike got into Lake Davis in the first place, but one theory is that they were deliberately introduced by anglers who prize the pike’s fighting qualities. Another is that the pike were first introduced into nearby Frenchman’s Lake, then made their way into Lake Davis.
In 1997, authorities poisoned Lake Davis with rotenone, which removes oxygen from the water, in an attempt to kill the pike. The effort outraged local residents, partly because the lake was a drinking water source for nearby Portola, and partly because closing the lake crippled the local economy. In 1998, the state approved a nearly $10 million settlement to help the local economy, an amount that was dismissed as adequate by local business interests, who complained that it was too little, too late.
But the following year, the pike somehow came back to Lake Davis.
The state operations have been a political flash point at the lake and in nearby Portola, where many local residents complained that the state had devastated the local economy, which depends heavily on the lake. Fishing guides, bait shops, retailers and motel owners, among others, said the state’s actions forced a huge drop in business and group called Committee to Save Lake Davis was formed to challenge the state. Environmentalists complained, too, contending that the long-term impacts of rotenone were uncertain. Many Portola residents were angered that the anti-pike operation targeted the city’s principal drinking-water supply.
During the 1997 treatment, Lake Davis captured international attention. There were also arrests: Seven people were taken into custody as Fish and Game agents in two-dozen boats scattered across the seven-mile-long lake to distribute the rotenone, some 16,000 gallons of liquid and 60,000 pounds of powder. Four people in wet suits and on inner tubes were arrested when they chained themselves to a buouy, while the other three were arrested for moving the shore markers used by the boats for the operation.
Now a new effort began this week, for more extensive than the other two. Using satellite-generated data as a guide, state authorities this week began treating the streams and tributaries that feed Lake Davis, a scenic Sierra lake north of Portola about 140 miles northeast of Sacramento. State Fish and Game Department authorities crafted a grid map of the lake and its feeder streams, and they intend to gradually treat the streams with rotenone as they move toward Lake Davis. In the finale of the operation, the lake is scheduled to be treated over two days with rotenone–a chemical that removes oxygen from the water–beginning Sept. 25.
Opponents note that rotenone contains the chemical TCE, a known carcinogen, but authorities say the amount of TCE that actually enters the water is diluted to less than 0.5 parts per billion–about a tenth of the amount legally allowed in a municipal water supply.
The rotenone, which turns the water an eerie green, lasts about 48 hours, and then the water returns to its natural color. It kills not only the pike, but the other fish in the lake. After the treatment, state officials must collect the dead fish, then restock the lake with trout. After the 1997 treatment, the state put 750,000 trout back into the lake.
State authorities hope the latest operation will be less controversial–and thus far, that has been the case. There are several reasons. First, the Committee to Save Lake Davis appears to be less active than earlier. Second, the lake is no longer is the source of drinking-water for about 20,000 people in Portola and its environs. Third, the state has quietly prepared for the operation, and while there has been some media attention, it is less pervasive than before.
“It’s sort of under everybody’s radar,” one state official said.