Cruises of the r/v "Baldo Kosić" in the coastal region of the middle Adriatic Sea,1973-1974 – biomass of the net zooplankton

Abstract

        Investigation of the net zooplankton covered the coastal areas of the Middle Adriatic and was carried out from August 1973 till August 1974. The material was collected using the IOSN plankton net, 250 microns mesh netting, diameter 113 cm. Always a pair of vertical hauls were made from the bottom to the surface. For the dry weight, ash weight and organic content determination the dry-combustion method was used. Half of the material was used for counting the total number of individuals, copepods, cladocerans, larvae and »other groups«.

       The highest values of the most parameters were found in closed areas of the Kaštela bay and Marina bay. The maximum of the quantity was found during the summer cruise in 1974, and minimum values were present during the winter and spring cruises. Qualitative composition of the zooplankton shows that copepods are the most important group in the total number of individuals, especially in the winter season. Cladocerans have bigger amounts during the summer cruise and their relative abundance were even more than 60% of the total number. Other groups and larvae are present in a greater percentage only in some of the regions and seasons, and have no importance for the total zooplankton biomass.