Further Investigations of Goldfish in Eastern Washington Lakes and Evaluation of Electrofishing as a Tool for Conducting Removal Operations

摘要

In eastern Washington, goldfish (Carassius auratus L.) population control through wholelake application of rotenone is not effective and may actually contribute to the roughfish problem. Rehabilitation records of area lakes receiving chronic rotenone treatment reveals that following each application of rotenone, a reduction in species diversity accompanied by a shift in population structure toward roughfish has occurred. Therefore, one long-term effect of chronic rotenone treatment may be selection of resistant fish species that increase the rate of eutrophication and decrease water quality. The purpose of the study is to develop new techniques for effective roughfish control utilizing seasonal behavior patterns.