Working Group on the Integrated Assessments of the Barents Sea (WGIBAR)

  

The main objective of the Working Group on the Integrated Assessments of the Barents Sea (WGIBAR) is to perform an integrated assessment of the Barents Sea ecosystem taking into account climate change and anthropogenic impacts, and to provide ecosystem information to ICES working groups and various users (managers, stakeholders and others). To achieve this objective, the group prepared relevant datasets, performed comprehensive analyses, and discussed the state and trends of the Barents Sea ecosystem. 

The Barents Sea has experienced a warming trend since 1970s, while becoming colder after 2015-2016. Still, 2021 had higher air and water temperatures, less area covered by Atlantic water and slightly more ice compared to 2020.

Mesozooplankton biomasses in the southwestern and southcentral areas in 2021 were below the averages for 2016-2020, while in the southeastern regions generally comparable with the levels for the 5 preceding years. The spatial biomass distribution in the Barents Sea in 2021 displayed a typical pattern with high levels in the southwestern, deep central-eastern and northern regions, and low levels in the central and eastmost regions. In 2021 the total biomass of euphausiids was relatively high and was higher than the previous 5 years and long term mean (2003-2021).

Strong year classes of cod and haddock, intermediate year classes of capelin and herring, while weak year classes of polar cod and redfish occurred in 2021. The total biomass of 0-group was slightly below long term mean and was close to 1 million tonnes.

In 2021 total biomass of capelin increased to 4 million tonnes, which is higher than the long-term average. Polar cod biomass index is still at a high level, but slightly lower than in 2020. The numbers and biomass of young herring in 2021 in the Barents Sea decreased compared to 2020 and was at a record low level. 

Most of the main demersal fish stocks (cod, haddock, Greenland halibut, beaked redfish, long rough dab, saithe) in the Barents Sea are in a healthy state and at a level at or above the long term mean. The exception is the golden redfish stock, which is still depleted. Stocks of cod, haddock and Greenland halibut will most likely continue to decrease in 2022-2023. The other stocks are expected to be relatively stable in the near future. 

Diet composition of cod in 2021 was similar to 2019-2020. Importance of shrimp, snow crab, capelin, polar cod and juvenile cod has increased in cod diet, while importance of euphausiids, hyperiids, herring and juvenile haddock has decreased.

In recent years, the northern shrimp stock has remained stable, showing fluctuations but without a clear trend. The distribution of snow crab and red king crab has not significantly changed in 2021.

The distributions of the marine mammals in the Barents Sea in 2021 was quite similar to previous years. Distribution of baleen whales to a certain degree overlapping with the capelin distributions. 

Concentrations of most contaminants in fish and crustaceans in the Barents Sea are relatively low compared with other sea areas and the levels are either stable or decreasing. Amount of plastic and other litters in 2021 was the same, as in 2020. No abnormal microplastic contamination of the surface waters of the Barents Sea was detected in 2021.