Analyses of 402 samples collected from late March through early June in 1980 have shown that the two communities of zooplankton over the southeastern shelf of the Bering Sea are kept separate spatially by the lack of advection and frontal characteristics of the salinity distributions. The abundance of copepods over the middle shelf, between 50 and 100 m isobaths approximately, was highly correlated with seasonal warming of the surface layer, while abundances of copepods over the outer shelf and slope were not. The spring bloom of phytoplankton influenced abundances over the middle shelf more profoundly than the outer shelf; of the twelve taxa which composed most of the biomass of copepods over the middle shelf, eleven were significantly more abundant during the bloom than they were prior to the bloom. Over the outer shelf, only six of eighteen taxa were significantly more abundant during the bloom, and over the slope, three of eighteen. Differences in abundance of copepods between domains and among stations within each domain were greatest early in the study. During the study, stations of each domain became more similar in the abundance of their characteristic taxa.