 Following an explosion of the pike population, and the California Department of Fish and Game (DFG) decided to treat the reservoir with rotenone, a naturally occurring poison deadly to gilled creatures.After the first attempt failed to eradicate the pike and the population rebounded, the DFG again utilized rotenone in September 2007, after lowering the water level.DFG's justification for the action was their concern that pike might escape the lake and enter the Sacramento River system, potentially harming native anadromous fish species such as steelhead and salmon.