Age and growth of 151 creek chubs, Semotilus atromaculatus, from the Des Moines River in 1961 were determined by scale and length-frequency methods. The body scale relationship had an intercept of 8.3 millimeters in total length. Chubs reached total lengths of 58, 95, and 128 millimeters at the formation of the first, second and third annuli respectively. Annuli form in May. Weight increased approximately as the cube of the length. The most important food items were plant material, aquatic insects, and, in the case of larger chubs, fish. The chubs were found adaptable in their food habits with the changing conditions of the river
