This is a cooperation between Institute of Marine Research (IMR) in Norway (contact person Tor Knutsen, tor.knutsen@imr.no ) and Polar Research Institute of Marine Fisheries and Oceanography (PINRO) in Russia. Main objective of the network: 1. Determine amount and distribution of zooplankton biomass (in three size fractions). 2. Describe abundance of dominant zooplankton species. 3. Determine annual variation in zooplankton biomass and feeding conditions of planktonfeeding fishes. Operation: Observations are taken by IMR from research vessels. The programme is carried out in cooperation with Russia (PINRO).