Test seining in East Okoboji Lake, Dickinson County, Iowa, in 1940 revealed a large population of rough fish and relatively few game fish. The Iowa Conservation Commission therefore intensified its rough-fish removal activities on the lake. Following several years of this expanded program, significant increases of game fish occurred. These increases are reported in the form of comparative data on catch per unit effort over a period of 12 years, from 1940 to 1951. General observations indicated an improved environment for game fish and an increase in angling success.