A significant correlation was observed between satellite derived chlorophylla(Chla) concentrations and the biomass of the invasive comb jellyfishMnemiopsis leidyiin the southern Caspian Sea. By consuming the herbivorous zooplankton, the predatory ctenophoreM. leidyimay have caused levels of Chlato rise to very high values ( mg ) in the southern Caspian Sea. There might also be several other factors concurrent with predation effects ofM. leidyiinfluencing Chlalevels in this region, such as eutrophication and climatic changes which play major roles in nutrient, phytoplankton, and zooplankton variations. The decrease in pelagic fishes due to overfishing, natural, and anthropogenic impacts might have provided a suitable environment forM. leidyito spread throughout this enclosed basin.