The white bass were probably originally stocked in Spirit Lake, northwestern Iowa, in the last 50 years and were not native to these waters. The numbers have shown great fluctuations over the years. The field work for the present study covered the period 1941 to 1946.

Spirit Lake is a shallow, rich, hard water, eutrophic lake not exceeding 23 feet in depth. Potamogeton richardsonii and Scirpus acutus are the dominant deep-water plants. In general, young pan and game fish amounted to a very large percentage of all of the small fish in the lake during the years 1941, 1942, 1943, 1945 and 1946. The young of yellow perch, black crappie, white crappie, bluegill and black bullhead constituted all of the small pan fish for these years. Young white bass were quite common in 1942; young large-mouth black bass were common in 1943, 1945 and 1946. The number of small pan fish was always many times greater than that of the young game fish. Adult yellow perch and black bullhead were very abundant for every year considered.

The age and growth of the individual white bass were determined by the scale method. The body-scale relationship of the white bass can be described as a regression line having a Y intercept (length axis) of 23.9 millimeters and a slope of 1.88. Females grew faster and larger than the males, but they did not live as long. The 1941 year class dominated the population from 1942 through 1946.