Estimates of individual carbon masses of zooplankton taxa from the NE Atlantic and NW European shelf, based on ring nets and Continuous Plankton Recorder

Zooplankton are enumerated in units of numerical concentration, but the taxa range over many orders of magnitude in individual body size, so it is hard to know whether the taxa that dominate numbers are also important in terms of biomass. Budgets, models and many other studies of the food web tend to prefer zooplankton data in units of carbon concentration, which makes the use of many datasets problematic. Here we have compiled 579 zooplankton individual carbon mass determinations for a wide range of net-caught metazoan zooplankton, based on two Continuous Plankton Recorder (CPR) data sources and two ring-net derived data sources, namely from Plymouth L4 and the Marine Directorate (various sites in the North Atlantic). We have used these data sources, alongside expert judgement from CPR analysts, to obtain individual carbon mass “best estimates” for the consistently identified CPR taxa that are used within the Plankton Lifeform Extraction Tool (PLET) for policy reporting. By combining appropriate estimates of individual carbon masses with abundance data, users can estimate biomass concentrations of zooplankton species or groups. The metadata describes the data construction and individual column headings, how the data were obtained, with pointers and caveats to their use. Please use the data citation above when using these data. This 5 February 2026 version of the data supersedes an earlier version (filename dated 4 November 2024) following expert advice on how Calanus species are identified, with carbon mass estimates of Calanus finmarchicus, Calanus helgolandicus, Calanus glacialis and Calanus hyperboreus increasing to 87, 62, 223 and 720 µg respectively.