Lake Davis Pike Eradication Project EIR/EIS

The purpose of the project is to eradicate the Pike from Lake Davis and its tributaries. Pike is a fish that is considered to be a voracious predator that is likely to invade other water. The EIR/EIS was presented by the California Department of Fish and Game (DFG) and the U.S. Forest Services (USFS). Since they were reappeared in 1999, they have adversely affected the ecology of the Lake, as well as, the trout fishery. The authorities are concerned with the idea of some Pike escape from the Lake affecting other areas.

1980 Pike were illegally introduced into Lake Frenchman,
1994 Pike appeared in Lake Davis
1997 Approached to eradicate by rotenone
1999 Pike reappeared in the lake.
2000 the Lake Davis Steering Committee was from
2000-02 Pike catch and catch-per-unit-effort increase rapidly
2003 Committee sent a letter Secretary for Resources, requesting that the DFG investigate the methods to rid Lake Davis of pike
2004 Secretary of Resources directed DFG to study eradication options
2005 Released Project Proposal to Public (NOP/NOI);
Public Scoping; Scoping Meetings
Feb- 2006 Consultant Hired to Prepare EIR/EIS
Aug- 2006 Release of Draft EIR/EIS
Aug-Sept 2006 Public Review and Comment
Jan- 2007 Final EIR/EIS; Certifiaction EIR; Obtain Permits; Mandatory 30-day Review Period (NEPA); Notice of Determination/Record of Decision

The California Department of Fish and game (DFG) proposes the eradication of the northern pike (Esox lucius), from Lake Davis and its tributaries. The project is designed to help protect the fishery and other aquatic resources of Lake Davis. The northern pike are restricted in California due to have been found to pose a threat to other species and also the ecosystem where they habitat.
Pike are a non-native, invasive species that have devastated the local fishery and have had a subsequent negative impact on the local economy since 1999, when they reappeared after a controversial pike eradication project in October 1997. Despite control and containment efforts since 2000 several pike have been taken from the reservoir since then - the pike population continues to grow. If they escape, pike could cause irreversible ecological and economic harm to other areas of the state, including the Sacramento-San Joaquin River Delta.
The objective of the project is to successfully eradicate pike from Lake Davis and its tributary. The secondary objectives are to carry out the project faster to reduce the ongoing impact of the pike in the lake, to use a method that has been proven to be effective in experiment in laboratories, to comply with the existence laws to protect public health and safety and minimize the environmental impacts.


Lake Davis is an artificial reservoir impounded in 1966-68 by the creation of the Grizzly Valley Dam on Big Grizzly Creek. The reservoir is feed by three main tributaries, Big Grizzly, Freeman, and Cow Creeks. Northern Pike were illegally introduced in Frenchman Lake in the late 1980s, and successfully eradicated from that area in 1991. In 1994 pike were observed in Lake Davis in 1994, years later, in 1997 there was a first unsuccessful attempt to eradicate from the lake by using chemical treatment.
When authorities realized that pike were not eradicated, in 1999 the Lake Davis Steering Committee was created, composed by citizen and elected city and county officials, including the participation from the state and federal agencies. Many experts from other states participate in the assessment of the situation at the lake, and they agree that Lake Davis provides the habitat for successful pike reproduction and also could affect the other species.
In 2000, DFG and the committee developed a management plant where they recommended strategies to decrease the population of pike. The recommendation included education, law enforcement, netting as well as experimental method of using detonation cord. Regardless of the management plant, the DFG found out that after three years (2003) the population of pike continued to increase. After this result, in December of 2003 the Committee sent a letter to the Secretary of Resources requesting DFG to investigate methods to eradicate the pike from Lake Davis, addressing economics issues as well as public health protection. Five months later, DFG presented to the community a list of different methods, which has been suggested by various agencies and people.

Project Description

The project consists in decrease the volume of the lake to a approximately 45,000-48,000 acre-feet and then, it will be an application of rotenone, a common piscicide The application of liquid rotenone would be by boats, raft or other flotation devices. The application on the water streams would be by drip stations and hand-type spray bottles, sprayers, backpack sprayers or other similar devices. Aerial spraying will also be considered for some areas such as wet seep.
Rotenone eventually will break down due to its characteristics within 14 to 45 days. Temperature, sunlight and turbidity of the water are factors that will increase or reduce the break down. To neutralize rotenone exist different technologies. The use of some chemicals like potassium permanganate will reduce the time to neutralization. But the application of this chemical should be carefully because is considered toxic.
Due to the use of pesticide, DFG determined that monitoring and mitigation will be to surface water quality, groundwater and air quality.


Four public scoping meeting were held prior to preparation of the EIR/EIS. Two of them were perform at Portola, California and the last two in Sacramento, California.
The resource investigated were those were determined to be potential affected by the proposed project and alternative project

Environmental Consequence

Physical Environment
Surface Water Resources
• Bank erosion on Big Grizzly Creek,
• Tributary incision,
• Structural instability of boat ramp,
• Water quality parameters of turbidity, dissolved oxygen, bacterial level, nutrient and water temperature.
Ground water
•Change in water level,
•Change in water quality.
Air Quality
•Air pollution from equipment,
•Dust from construction and from unpaved roads.
•From transportation
•From airboats
Biological Environment
Aquatic Resources
•Potential for escape of pike to the Central Valley;
•Temporary loss of aquatic habitat in Lake Davis;
•Application of harmful chemicals into Lake Davis and its tributary streams and springs;
•The dewatering of Lake Davis, tributary streams and springs, and Big Grizzly Creek downstream of Lake Davis;
•Accidental spills of chemicals into the environment; and
•Change in flow regime in the Creeks.
•Exposure of terrestrial wildlife to rotenone through direct contact, ingestion of treated water,
or consumption of fish killed by rotenone;
•Impacts associated with the drawdown of Lake Davis and the resulting reduction of aquatic and wetland
habitats as used by terrestrial wildlife;
•Impacts to fish-eating terrestrial wildlife due to treatment of Lake Davis with rotenone and the temporary
reduction of the fish community;
•Impacts to insectivorous terrestrial wildlife due to treatment of Lake Davis with rotenone and the temporary
reduction of the aquatic invertebrate community; and
•Impacts to terrestrial wildlife due to disturbance associated with treatment activities at Lake Davis and its
•Loss of terrestrial, riparian, wetland and special plants;
•Spread of noxious weeds.
Human Environment
Land Use and Land Management
•Forest management issues; and
Aesthetic Resources
•Views of exposed lakebed; and
•Appearance of Big Grizzly Creek following neutralization.
Cultural Resources
•Ground disturbance from project activities affecting cultural resources;
•Erosion from reservoir drawdown affecting cultural resources below the water surface; and
•Looting of cultural resources exposed by reservoir drawdown.
Recreation Resources
•Displacement of recreation to Frenchman Lake; and
•Loss of tourism at Lake Davis.
Economic Resources
•Local economic activity;
•Effect on local fiscal resources;
•Loss in economic value of recreation at Lake Davis;
•Drop in property values;
•Water supply cost and benefits; and
•Statewide economic effect due to reduced commercial and recreational fishing.
Public Services
•Law enforcement;
•Fire protection and other emergency services;
•Domestic public water supply/water treatment; and
•Downstream water supply.
Human and Ecological Health Concerns
•Effect of use and transport of rotenone and its formulation constituents on human populations;
•Effect of spill of rotenone and its formulation constituents on human populations; and
•Effect of rotenone and its formulation constituents on fish and wildlife species.
Social Issues and Environmental Justice
•Demographics of human populations;
•Effects on minority populations; and
•Effects on low-income populations.

The first alternative is the no project no action. The four alternatives proposed in the project involved rotenone treatment at different draw downs. Two other alternatives proposed at the same volume of the lake with different rotenone treatment (liquid and powder). The last alternative is the one where no chemical is used.


After CDFG officials dicovered that Pike had illegally introduced in Lake Davis in 1994, they were concerned that pike would make their way downstream from Lake Davis into the Bay-Delta system, where a new predator could harm both commercially important and endangered native fish species. Pike is a popular Midwestern sport fish, but at the same time, posed a threat in Lake Davis. The local economy depends on a healthy trout fishery, which is imperiled by the presence of the predatory pike. To get rid of the invasive pike, the California Department of Fish and Game decided to poison the lake and kill the pike using a pesticide. Residents in the nearby town of Portola, which gets its drinking water from Lake Davis, were outraged.

Geographic Area: 
Lake Davis is located in Pumas County, California, at elevation 5,777 feets above see level.