Quantitative and qualitative distribution of appendicularians population in the open waters of the Adriatic Sea

Abstract

       This paper presents the results of the investigations in the horizontal distribution of appendicularian populations in the open waters of the Adriatic Sea from Portorož to Otranto. Zooplankton was sampled on 4 seasonal cruises (1974/76) with the boat »Andrija Mohorovčić« Hydrographic Institute of the Yugoslav Navy. During these investigations, 27 species of appendicularians were identified, 8 of which appeared for the first tine in the Adriatic Sea (Pelagopleura haranti, Fritillaria gracilis, F. messanensis, F. venusta, F. me­gachile, F. fagei, F. fraudax, F. urticans). According to their numerical value and abundance, all the species were classi­fied in four groups. There was an indication that the sea­sonal and spatial variations in the number of appendicu­larians depend greatly on the behaviour of the more nume­rous and frequent species (Oikopleura longicauda, O. fusifor­mis, O. dioica, F. pellucida and F. borealis), which, averaged together, account for 90.8% of all appendicularians.