This report is a contribution to the Strategic Environmental Assessment (SEA5) conducted by the Department of Trade and Industry (now Department of Energy and Climate Change). This report provides data on the plankton community in the SEA 5 of the North Sea. Data for this report were provided by the Continuous Plankton Recorder Survey, as well as sourced from outside organisations. The SEA 5 area is influenced by the Shelf Edge Current, which breaks off its main route in the form of the Fair Isle Current, the Dooley Current and the East Shetland Inflow. Oceanic water flows into the North Sea in this area, causing periodic incursions of associated planktonic organisms. The report addresses: phytoplankton and zooplankton community composition; Phytoplankton blooms; Abundance of the copepod Calanus; Mero-, pico- and megaplankton; Phytodetritus and vertical fluxes.