Pan-North Pacific comparison of long-term variation in Neocalanus copepods based on stable isotope analysis

► We study spatio-temporal variation of Neocalanus δ15N over the North Pacific. ► Neocalanus δ15N is high as region-specific seasonal nitrate drawdown is high. ► Mechanisms of interannual variation in Neocalanus δ15N differ among regions. ► Neocalanus δ15N is useful to detect change of lower trophic level environment.