Gelatinous invertebrate zooplankton of the South Adriatic: species composition and vertical distribution

The species composition and vertical distribution of gelatinousinvertebrate zooplankton were investigated from April 1993 toJune 1994 in the 0–1000 m water column at a deep-sea stationin the northern part of the South Adriatic Pit. Fifty-sevenspecies were identified: 11 hydromedusae, 13 calycophores, 3ctenophores, 3 heteropods, 10 pteropods, 8 polychaetes and 9chaetognaths. The pteropod Desmopterus papilio and the heteropodProtatlanta mediterranea were recorded for the first time inthe Adriatic Sea. Data from this study differed from those ofprevious investigations in the South Adriatic as regards thenumerically dominant polychaete and pteropod species. All investigatedgroups generally were more abundant in the upper 100 m and decreasedwith depth. Different vertical distributions of life stageswere observed for those species that occupy a wide depth range:Persa incolorata, Solmissus albescens, Limacina inflata, Cymbuliaperoni, Pelagobia longicirrata, Sagitta lyra and Sagitta decipiens.