Characteristics of Biomass and Production of Cladoceran Zooplankton in Lake Kasumigaura

Abstract

Studies on population dynamics, biomass and production of cladoceran zooplankton in various regions of Lake Kasumigaura were conducted from 1983 to 1985. Seasonal changes in species composition were similar among the regions, but were different among the years. The biomass and production of cladocerans were usually higher in the summer than in the other seasons. Those in the spring and fall were often suppressed by a predator, Neomysis intermedia. Bosmina fatalis, which dominated the cladoceran community in the summer and fall, contributed to the annual biomass and production of the total cladocerans with the highest percentage. The biomass, production and P/B ratio of cladocerans, and the energy transfer efficiency from phytoplankton to zooplankton were higher in Takahamairi Bay and Tsuchiurairi Bay than in the central region of the lake. © 1987, The Japanese Society of Limnology. All rights reserved.