Zooplankton have been monitored on autumn cruises in the Barents Sea since the late 1980s. The time series shows a pronounced peak in zooplankton biomass in the inflow region of Atlantic water in 1994. The mean biomass was ~ 20 g dry weight m, which is more than twice the long-term average, and showed an atypical composition with dominance of the small size fraction (<1 mm). Analysis of stored samples revealed that the high biomass event in 1994 was due to a mass occurrence of two species of pteropods ( and ) dominated by small juveniles < 1 mm in diameter. High biomass in the Atlantic inflow region also in 1995 was due to a strong but delayed summer generation of the dominant copepod . Estimated biomass of copepods (from numbers and individual weight by species and stage) was strongly dominated by in both years (~90%). The average biomass of spp. in 1994 was ~ 7 g dw m, estimated to be mainly in the small fraction, and contributed to the 1994 peak on top of a "typical" biomass of . The results contribute to a better understanding of the Barents Sea ecosystem.
