Predation can be a potent force structuring ecological communities and affecting several trophic levels. The cascading trophic interactions hypothesis predicts that lacustrine predators such as fish can have a strong effect on herbivorous zooplankton, which in turn can regulate phytoplankton. Ascertaining the scale, scope and generality of this hypothesis is important for both development of ecological theory and aquatic ecosystem management. Although small-scale tests of parts of this cascade are common, whole-lake assessments are not, particularly in large, natural lakes; also the influence of several trophic levels and nutrients, a requisite for unambiguous interpretation of predator effects, has not been considered...