EARLY RESPONSES OF PLANKTON AND TURBIDITY TO BIOMANIPULATION IN A SHALLOW PRAIRIE LAKE

We evaluated the effect of a fish removal from a shallow, turbid, eutrophic lake. By late May (following an October fish removal), the cladoceran community shifted from small-bodied Bosmina and Chydorus (less than 100 l-1) to larger Daphnia (over 100 l-1). During the periods of peak daphnid abundance (late May-June) chlorophyll-a concentrations and edible diatoms were reduced and water transparency improved dramatically. Total phosphorus was not significantly lowered during this period. Although this clear-water phase was short-lived (May, June and early July), it corresponded to the critical period of plant growth and allowed dramatic increases in submergent macrophytes. © 1990 Kluwer Academic Publishers.