Structure and long-term changes of polychaete communities of the Varanger fjord in 2003 and 2019

Long-term changes in species composition, production indicators, and structure of polychaete communities for the period of 2003 and 2019 in the Russian part of the Varanger fjord (Barents Sea) were shown. The connection of such changes with climate factors and the influence of the red king crab are considered. The changes in species composition, structure, and production characteristics of polychaetes in the Russian part of the Varanger fjord (Barents Sea) in 2003 and 2019 are shown. The linkage between these changes and the climatic factor, as well as the influence of the introduced red king crab Paralithodes camtschaticus (Tilesius, 1815), is discussed. The results demonstrate an increase in the quantitative characteristics of polychaete Spiochaetopterus typicus M. Sars, 1856, indicating a decrease in pressure from the king crab on bottom communities. The biodiversity indices indicate the absence of negative changes in the settlements of polychaetes in the Varanger fjord during the studied period.