Fishery survey and related limnological conditions of Williams Lake, Hubbard County, Minnesota

Bluegill (Lepomis macrochirus), pumpkinseed sunfish (Lepomis gibbosus), largemouth bass (Micropterus salmoides), yellow perch (Perca flavescens) rock bass (Amploplites rupestris), black crappie (Pomozis nigromaculatus), and northern pike (Esox lucius) were found in Williams Lake, Hubbard County, Minnesota, during a fishery survey of the lake in late August 1982. The most abundant fish were the bluegills. These fish live in the large littoral zone of the lake; this zone underlies 55% of the surface area of the lake. The most ubiquitous benthic invertebrate in the littoral zone (amphipods) and the most abundant benthic invertebrate (chironomid larvae) were major food sources for the bluegill. Other organisms found in the stomach contents of fish collected in this survey were zooplankton, gastropods, Diptera larvae, odonates, terrestrial insects, and other fish. Daphnia were the only zooplankters of a diverse plankton community that were found in stomach contents. The abundance of fish other than bluegill was typical for a system in which northern pike is the major predator.