Reliability of spatial and temporal patterns of C. finmarchicus inferred from the CPR survey

• abundances of all copepodite stages of C. finmarchicus are maximal above the thermocline, whatever the time and the season
• the abundance in surface remains correlated down to 100 m
• the abundance estimated by the MOCNESS-1 nets was positively correlated with the abundance estimated from the CPR survey
• spatial distribution of C. finmarchicus estimated from the CPR and from other surveys were positively correlated in space

The Continuous Plankton Recorder (CPR) survey has collected plankton since 1958 in the North Atlantic Ocean and its adjacent seas. Among all species recorded by the CPR, Calanus finmarchicus has probably been the most investigated species because of its ecological importance for the temperate and subpolar regions of the North Atlantic Ocean. However, abundances of C. finmarchicus assessed from the CPR survey have been rarely compared to more traditional sampling methodologies. In this study, we examine and compare spatial (surface and vertical) and temporal (diel and seasonal) patterns in the abundance of C. finmarchicus with another sampling technique in the gulf of Maine. Our results provide evidence that the CPR survey not only gives internally consistent time series of C. finmarchicus, but also an accurate representation of both spatial (surface and vertical) and temporal (diel and seasonal) patterns.