Distribution of the copepodite stages of Calanus finmarchicus from Lofoten to the Barents Sea in July 1989

The zooplankton biomass in the Barents Sea can vary by an order of magnitude from year to year. One reason for the large change is the varying transport of Calanus finmarchicus from the Norwegian Sea into the Barents Sea. How much of the population is stationary in the Barents Sea and how much is transported from the Norwegian Sea is unknown. Zooplankton samples were collected along the coast of North Norway from Lofoten and into the Barents Sea during the early juvenile fish survey in July 1989. The samples were evaluated with special emphasis on Calanus finmarchicus, which were sorted to copepodite stage. The probable drift route of the zooplankton and its origin were determined by examining the distribution of the different stages and the currents. The different stages were in very distinct bands, with the youngest stages in the south and the older stages in bands stretching east-west, with stage CV farthest north and east. When these patterns are compared with currents in 1989, the results support the theory that a large proportion of the C. finmarchicus stock is transported from the Norwegian Sea into the Barents Sea. (C) 2000 International Council for the Exploration of the Sea.