Effects of temperature on zooplankton population dynamics in the Barents Sea vary on a range of temporal, spatial and developmental scales

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Temperature is considered the major factor shaping marine zooplankton dynamics, including distribution, abundance and phenology. During the past decades, the Barents Sea experienced strong temperature fluctuations, but previous studies have failed to show a clear link between temperature variation and the dynamics of the abundant copepod species Calanus finmarchicus. We have analysed a Russian time-series covering Atlantic waters of the Norwegian Sea and the Barents Sea, spanning from 1959 to 1993. This dataset with high spatial resolution includes information on both total copepod biomass and abundances of different life stages of C. finmarchicus. We investigated associations between temperature and C. finmarchicus abundances across separate life-stages and on various spatio-temporal scales, and found differing patterns that would be masked with a coarser data resolution. The results indicate associations between temperature and abundance, distribution and phenology of C. finmarchicus. C. finmarchicus is a primary food source for many fish species in the Barents Sea. Temperature effects on the dynamics of this species are therefore likely to have both ecological and economic importance.