Mouth diameter of the net was 113 cm, mesh size 200 µm. Sample aliquots were immediately immediately utilized for biomass measurements. Volumes of filtered seawater were estimated by multiplying the area of the net mouth by heights of sampled layers from winch readings. Total mesozooplankton biomass was measured as dry weight on a fresh aliquot of an original sample. The samples were filtered through pre-weighed GF/C filters, briefly rinsed with distilled water to remove salt, dried in an oven at 60 °C for some hours onboard and preserved frozen. Later in the lab, the samples were dried again in the oven for 24 hours and then weighted on a microbalance.