Abstract:

A total of 90 species of zooplankton were found and recorded in samples collected in the Bering Sea (55° 59′-60° 40′N, 173° 21′E-175° 54′W) by the Chinese First Arctic Scientific Expedition during the period from July to August in 1999. These species can divided into 4 ecological groups of arctic, sub arctic, oceanic cool water and world wide eurytherma, The most important group was sub arctic whidh was dominated by Eucalanus bungii , Calanus plumchrus , C. cristatus and Metridia pacifica and characterised by sub arctic community of the pacific ocean. The total zooplankton biomass reached 425.4mg/m 3 , showing a high to low biomass distribution from south to north and from peripheral to centre. Vertically, it was high (43%) in layer of 50-0m and low (8.4%) in layers of 200-100m in deep waters (<500m) and the pattern varied significantly with maximum biomass moving to deeper waters during the daytime and toward the surface at night in shallow waters (<100m). The distribution of populations were different in water layers and ever it varied with different developing stages for the same population.