Zooplankton biomass and species distribution is monitored during the joint autumn ecosystem survey. Joint Russian and Norwegian zooplankton investigations have taken place since 2002. Regular sampling by IMR began in 1979 while PINRO has conducted these surveys since in 1982-1993. A Juday net (37 cm in diameter, 180μm) is used to obtain zooplankton samples by PINRO. IMR uses a WP2 net (56 cm in diameter, 180μm) and a 1m2 MOCNESS multiple plankton trawl with 9 nets all having a mesh size 180 μm, as standard zooplankton gears.