SESTON AND ZOOPLANKTON OF THE BERING SEA AND THE NORTH-WESTERN PACIFIC

For the Juday plankton net with mesh size 178 mk in the layer 0 - 100 m in the western part of the Bering Sea and adjacent regions of north- western Pacific, the ratio of seston biomass (as estimated by the wet weight of the plankton) to zooplankton biomass (as estimated by means of individual wet weight tables and of formulae for wet weight calcula ting from specimen size) was derived. The ratio changes with season, r eaching its maximum in fall and winter(1.68) and minimum in spring and summer (1.28 and 1.49 respectively). It was shown that in spring and summer the value of the ratio may be underestimated significantly. The ratio of zooplankton biomass, derived with the Juday plankton net wit h mesh size 178 mk in the layer 0 - 100 m, and seston biomass, derived with the NORPAK net with mesh size 330 - 350 mk in the layer 0 - 150 m, equals 1.46. The calculations show that seston obtained by the NORP AK net consists predominantly of zooplankton.