Motivation: I describe the GIS that is based on a database of zooplankton collected by Juday net with 0.1 m^2 opening (0.168 mm mesh) Main types of variable contained The average density (mg/m3) of plankton and their different constituents in one-degree trapeziums Location: Chukchi, Bering, Okhotsk, Japan/East seas, Pacific Ocean Time period: 1984-2013 Taxa studied: All mesofauna – more than 214 species of holo- and meroplankton Methods: GIS creation, data analysis and literature review Software format: Any that is capable of working with shapefiles Results: Maps of the spatial-temporal distribution of plankton with various taxonomic groups and dimensions were compiled and analysed. Based on these maps and on the literature, a supposition was made regarding the negative correlation of the zooplankton size with temperature. It was also revealed that some fluctuations in the abundance of plankton in the Bering Sea and the ocean are in phase, while in the Sea of Okhotsk and the Sea of Japan, the fluctuations are fully out of phase. In particular, during the transition from the light to dark time of the day in the Sea of Okhotsk and Sea of Japan, the density of plankton almost everywhere throughout the epipelagic zone increases; however, in the Bering Sea and the ocean, over large parts of the water area, it decreases. This means that the common practice employed by trophologists of attempting to replace the day-time catch in plankton nets with the night-time catches to assess the food reserves for fish will give significantly different results in these waters. Main conclusion: This unique GIS could be useful for understanding patterns and drivers of plankton biomass variations at large scales. Unfortunately, due to lack of funding, it has not been brought to the levels of species and development stages that could be available in the final release