Gifu Prefectural Research Institute for Freshwater Fish and Aquatic Environments, Kakamigahara, Gifu 501-6021, Japan
We examined the effectiveness of removal by angling in order to control the population size of the invasive exotic bluegill in Hananoko Lake, Gifu, Japan. A total of 15,966 individuals were caught by angling. Estimates based on a mark-recapture method revealed that the population size was reduced from 24,231 to 10,092 individuals over 15 months of population control. The change in the size distribution suggested that removal by angling not only reduced the number of potentially mature individuals but also decreased the recruitment of juvenile fish. This evidence indicates that removal by angling could control the population size of the bluegill, although a complete extermination by angling alone may be difficult.