Abundance of mesozooplankton in the Ionian Sea in April-May 1999@en

Mouth diameter of the net was 113 cm, mesh size 200 µm. Samples were immediately fixed with formaldehyde (2-4% final concentration) for specimen identification and counts. In some cases samples were split in two aliquots: 15/16 aliquots were fixed and 1/16 aliquots were maintained fresh 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. Identification and counts of specimens were performed on aliquots (1/5-1/10) of the fixed samples by using a graduate large-bore pipette. Copepods were identified to the species level and separated into females, males and juveniles (copepodites). All other taxa were identified at the species level when possible, or at higher taxonomic levels. Taxonomic identification was done according to the most relevant and updated taxonomic literature.