Abstract: Two navigation surveys in May (spring) and August (summer) of 2010 were conducted to investigate the species composition, abundance distribution, dominant species, and species diversity of diet zooplankton in the national protection area of aquatic germplasm in Lüsi fishing ground. In the study area, the abundance of diet zooplankton was higher in spring (163.1 ind·m^-3) than in summer (46.3 ind·m^-3), while the biomass was higher in summer (699 mg·m^-3) than in spring (324 mg·m^-3). Both the abundance and the biomass of the zooplankton were higher in the southwest than in the northeast. The dominant species in both spring and summer were Calanus sinicus, Labidocera euchaeta, Sagitta nagae, and Pseudeuphausia sinica. C. sinicus was in absolute superiority, followed by L. euchaeta. The index of species diversity was lower in summer (2.27) than in spring (2.51). Overall, the zooplankton community had a stable structure, which provided basis for supplying rich feedstuffs to the fishes, especially juvenile fishes, in this conservation area.

Key words: Platycladus orientalis sapling, instantaneous water use efficiency, short-term water use efficiency., soil water content