Observed Changes in the Largemouth Bass Population Since Construction of a New Pump Storage Reservoir at Charleston, Illinois

Lake Charleston, Illinois was electrofished to determine the status of the largemouth bass (Micropterus salmoides, Lacepede) population after its reconstruction into a pump storage reservoir. The changes observed were an increased rate of growth of the initial year class, increased average growth increment of older bass, and a more abundant bass population. Factors which may have influenced increased growth were decreased turbidity, alkalinity, and increased water level. There is a possibility the increase in water level led to an increase in terrestrial invertebrates as a food source, and increased spawning substrate and cover due to submerged terrestrial vegetation. In addition, the greater availability of utilizable forage fish (gizzard shad) may have affected increased growth