Experimental Study of the Impacts of Bluegill (Lepomis macrochirus) and Largemouth Bass (Micropterus salmoides) on Pond Community Structure

Abstract

We examined community impacts of bluegill (Lepomis macrochirus) and largemouth bass (Micropterus salmoides) in a summer experimental pond study of factorial design with four treatment combinations (fishless, bluegill, largemouth bass, and bluegill with largemouth bass). Ceriodaphnia reticulata, Daphnia pulicaria, Chaoborus sp., Volvox sp., anisopteran and zygopteran nymphs, and dissolved oxygen levels were suppressed in the presence of bluegill. Diaptomus sp., Conochiloides sp., Cyclotellas sp., Navicula sp., Oocystis sp., Anabaena sp., Ceratium sp., algal fluorescence, turbidity, 5- to 12.7-μm particles, and total phosphorus and total nitrogen were enhanced in the presence of bluegill. Daphnia pulicaria was enhanced and Cyclotella sp. and Oocystis sp. were suppressed in the presence of largemouth bass. Although the effects of the two fish were not independent, as indicated by significant bluegill × largemouth bass interactions for some plankton taxa, we found little evidence of bluegill impacts being reversed by largemouth bass. While total bluegill biomass was reduced and bluegill biomass distributions were shifted toward larger individuals, bluegill remained abundant in the presence of largemouth bass.