SEASONAL AND SIZE-RELATED CHANGES IN THE DIET OF NORTHERN PIKE FROM ASHALLOW PRAIRIE LAKE

Food habits of northern pike (Esox lucius) were documented in Lake Tho mpson, a shallow, windswept, eutrophic lake in eastern South Dakota. T he primary food items, assessed with the Relative Importance Index, ea ten by northern pike were common carp (Cyprinus carpio), crappies (Pom oxis spp.), and fathead minnows (Pimephales promelas). Common carp wer e eaten in midsummer and winter. Crappies were eaten primarily in the winter. Fathead minnows were an important food source throughout the y ear. Macroinvertebrates were consumed by northern pike up to 600 mm th roughout the open-water months. Northern pike in the smaller length gr oups (401-500 mm, 501-600 mm) ate primarily fathead minnows, juvenile common carp, and macroinvertebrates. Diets of larger northern pike con sisted primarily of larger common carp, juvenile crappies, leopard fro gs (Rana pipiens), and occasionally walleyes (Stizostedion vitreum).