Photo: Alison Bailey, NP.
Mesozooplankton biomass in autumn 2020 averaged about 7 g dry-weight m-2 for the parts of the Barents Sea that were covered. The spatial distribution of biomass across the Barents Sea displayed a typical pattern with high levels in southwestern and northern regions, and relatively low levels in central areas. Compared to the preceding 5 year averages, mesozooplankton biomass in 2020 was lower in the western, central, and eastern Barents Sea and slightly higher south and east of Svalbard. In the western subareas of the Barents Sea, including the region influenced by the inflowing North Atlantic Current, and where information on size-fractions is available, the decreased biomass in 2020 was mainly ascribed to the intermediate fraction (1000-2000 µm). This fraction mainly includes relatively large copepods such as older developmental stages of Calanus finmarchicus. Krill indices for biomass and abundances in the Barents Sea have shown increasing trends over recent decades.