Changes in biomass of macrozoobenthos in the eastern part of the Barents Sea during last century

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The Barents Sea, located on the border of the boreal and arctic zones, is one of the most productive fishery areas of the Arctic shelf. Benthos is an important component of the ecosystem of this relatively shallow sea. Knipovich Polar Research Institute (PINRO) has a nearly century-old history of the study of benthos in the Barents Sea, the latest of quantitative survey was carried out in 2003-2006. The analysis of the benthos biomass from the Russian part of the Barents Sea showed a considerable effect of climate on benthos biomass. During the cold period in the early 20th century, the average biomass of benthos in the eastern part of the Barents Sea was 149 g  m-2 . In the followed warm period (1930-1962) it increased to 230 g  m-2 . In the second cold period (1963-1988) the biomass of benthos reduced to 68 g  m-2 . The current period is the warmest during the whole interval of investigations in the Barents Sea. The average biomass of macrozoobenthos in 2003-2006 was 335 g  m-2 . The result of analysis showed that in the eastern part of the Barents Sea, where the influence of the fishery is low, the average biomass of macrozoobenthos was two- five times higher in the warm periods compare to the periods of cooling.