To help multifrequency acoustic data validation, zooplankton samples were acquired near each PIRATA buoy during FR26 survey. Oblique tows were conducted with bongo nets (300 µm mesh), towed between on average 200 m depth and the sea surface. A flowmeter (KC Denmark 23.090) mounted in the mouth of the net was used to measure seawater filtered during the tow. Samples were fixed in 4% formaldehyde buffered with borax for laboratory analysis and stored at -20°C. Mean filtered water volume was 175m3