Differences in the vertical distribution of bathypelagic zooplankton in the open northeast Atlantic and in the partially landlocked Levantine and Red Seas were re-evaluated to provide an interoceanic comparison. The decrease in zooplankton abundance with depth was most pronounced in the Red Sea and least evident in the northeast Atlantic. The Levantine Sea showed intermediate characteristics. The data plotted on a semi-log scale against a linear change in depth revealed a reduced rate of decrease in the zooplankton concentration with depth in the deep bathypelagic zone of the northeast Atlantic and the Levantine Sea. This pattern was also found for vertical profiles of micronekton abundance in the southeast Pacific. In the Red Sea, the decrease was exponential. Possible ecological mechanisms are discussed which might be responsible for these distribution patterns.