Abundance of microzooplankton (<200µm) in monthly samples collected between March 1990 and December 2015 at Station E2CO (A Coruña, NW Spain). Sampling made by vertical hauls of Bongo-type plankton net (diameter 20cm, mesh size 100µm until 1993-07-14, and diameter 30cm and mesh-size 40µm from 1993-07-14) between the surface and a maximum depth of 40m (until 1993-07-14) or 50m (from 1993-07-14). The net was equipped with a General Oceanic Flowmeter for the calculation of water filtered and a depth recorder. All samples were collected between 10:00 and 14:00 (local time) and were preserved in 2−4% sodium borate-buffered formaldehyde. Sub-samples were taken to estimate total zooplankton abundance (N m−3) by direct examination using a stereo microscope. Taxon names are referenced to the Word Register of Marine Species (last access: June 2019). Zooplankton identification and counts were made by M.T. Álvarez-Ossorio and E. Rey. These series are part of the long-term observational project RADIALES (Instituto Español de Oceanografía, IEO, Spain).