THE ROTIFERS OF LAKE PEIPUS

In the northern part of Lake Peipus, 140 taxa of rotifers were identif ied, with species of Anuraeopsis, Conochilus, Keratella, Polyarthra an d Synchaeta dominating. Two main periods of sexual reproduction occur, in the spring and autumn. Different life cycle patterns are represent ed. Rotifer number and biomass have two maxima between spring and earl y autumn. The contribution of rotifers to total zooplankton production varies from 13.6% (Oct.) to 89.8% (May). The average production of gr azing rotifers is 485.1 kJ m-2, while that of predatory rotifers (Aspl anchna) is 10.0 kJ m2.